This Page is broken down into three sections. The first will be related to mods that are meant for all Legacies. The second is concerned with modifications to BE/BH chassis 2000-2004 USDM Legacies. The third will apply to the 1990-1999 Legacy models, with some Turbo-exclusive content.
Every USDM Legacy has come with the same wheel lug patter, 5x100mm. Every USDM Outback, Impreza and Forester up to 2005, excluding the 05 STi, also has this same pattern. By this rationale, every wheel should fit every vehicle, This holds true as long as the wheel fits over the brake caliper. A 14"steelie from a 92 L will not fit over the brakes on a 91 turbo, or a 2004 GT. There are many, many Legacy GT, WRX and RS wheels available on public forums or ebay. Most can be had for a fair price with tires, and are a great improvelemtn over the small stock wheels on lower models.
I've always had good luck with Kumho Ecsta 712s. They're an affordable tire that comes in many popular sizes. The new Falken Ziel 512 fills a similar niche and i'm pleased with them on my BE. Tire choice is frequently decided by climate, so that's always a major consideration.
Brakes are another shared component across these lines. A 92 LS Wagon can use the front and rear brakes from a 2004 WRX with very little work and a step up to 16" wheels. The WRX has brought about a great number of used parts to the market and they're usually the same price as a good set of new rotors.
Pads usually come in three varieties: stock, dusty or rotor-eaters. Stock pads are quiet, meant to last a long time and don't wear rotors very fast. They don't stop on a dime either, but it's a compromise. Dusty pads sacrifice themselves for the good of the rotors, in general. They should stop better than the stockers as well. Rotor-eaters are usually high-friction metallic or composite pads that brake very well but tear rotors apart.
Subaru has always had a reputation for very reliable engines. The EJ-series was introduced in the 89 JDM Legacy and have evolved in both a turbo and normally aspirated form to offer from 165 to 300HP from the factory. Because of the similarities between the engines, may parts can be used between them.
BE/BH Chassis 2000-2004 USDM Legacy Sedan and Wagon
The 2000 Legacy model line was the first since 95 to offer only one engine choice: the Phase II SOHC EJ25. This is the same engine that the 2.5RS and Forester had in 1999, with improved torque across the engine's rev band. The car got a bit heavier, so any little bit of power is needed to get it down the road faster.
Because of the similarities between the Impreza and Legacy engine, nearly all bolt-on modifications work for either model. Several companies make cold-air or less restrictive intakes for both models. Borla, TWE and Cobb are some of the companies that produce headers and cat-back exhaust systems. Underdrive pulleys, earthing kits, upgraded MSD ignitions and fuel computers are available.
Finally, there are a few turbo kits available, but due to the lack of a hood scoop, either a replacement hood or front mounted intercooler would necessary.
The front of the BE/BH is similar to what Subaru has used in previous generations of the Legacy, but the rear setup is completely new for Subaru. Instead of a MacPherson strut setup, they decided to go with a multi-link arrangement mounted on a subframe assembly. This reduces the amount of interior space occupied by the suspension and is said to improve the rear handling. Because of these radical changes, new parts had to be made, and this has lead to a shortage of options for those looking to upgrade.
The USDM front springs are actually wider than the JDM ones, so swapping in overseas springs requires new struts/coilovers and new top mounts. Fortunately, any 90-99 Legacy or 93-02 Impreza top mount will work just fine. Cusco, TEIN and a few other companies have springs and coilover kits available.
The GT Limited model that i'm familiar with, in Sedan form, has a very small rear sway bar. It's perhaps 13-14mm at best. This is surprising, since the BC/BF Turbo models had 18 or 19mm from the factory. An upgraded rear swaybar should be pretty high on the list to improve turn in and reduce understeer, especially coupled with a rear LSD.
A front swaybar is probably a distant upgrade, because based on reports, JDM models don't fit because of clearance issues with the exhaust.
Endlinks are always a good upgrade to improve the performance and feel of the car. Whiteline, Prova and many more companies will carry replacements for the worn stock units. I have heard, however, that the OE parts use heim/spherical bearings and metal bodies. This means that they're very good from the factory.
One upgrade that isn't very common is something that Subaru did in later revisions of the Legacy model They added a subframe stiffener that attached between the unibody and the subframe in front of the wheels. I've seen it installed and heard that it does indeed make a difference.
Because the BE/BH chassis was the current Legacy model in Japan until recently, there are a wide variety of exterior modifications that can be done to enhance the look and feel of the car. Body kits, grilles and spoilers are just a few of the items that can be had at a fair price from vendors willing to import them.
One of the best modifications includes a simple swap of the stock USDM taillights for the JDM ones. The primary difference between the two is that the JDM parts have no amber whatsoever. The taillights on the JDM model are also slightly darker. A final note is that the JDM Legacy models spell out "Legacy" instead of "Subaru".
The headlight assemblies can apparently be de-oranged by either using a heat gun or baking the assembly till the orange pieces dislodge. This has been a proven method for the BD/BG and BE/BH models, more information is available by searching i-club and NASIOC.
One of the easier changes to the car would be to add a scooped hood. There are a few options to choose between if this interests you. The Baja Turbo, based on the BE/BH chassis, has an steel hood with a scoop and should be available in the US. A JDM hood can probably be imported as well, in steel or aluminum. Several companies can either import or make a Carbon-Fiber or Fiberglass replacement. Both of these are lighter than even the aluminum replacments, with fiberglass also being relatively inexpensive.
BC/BF and BD/BG Chassis 1990-1999 USDM Legacy Sedan and Wagon
Since the Turbos came with 15x6" alloy wheels, most are content with these, but for the performance and appearance minded, larger and wider wheels are available at reasonable prices. The 16x6.5" Legacy GT wheels is a favorite of mine as are the Impreza RS ones. These can usually be found either new from sites such as AAARims or TireRack, depending on the time of year.
Normall aspirated cars came with a minimum of 14" steel wheels with covers, but the LS and LSi models were frequently available with 14 and 15" alloy wheels. While not too large, and not too pretty, they beat a hubcap anyday. 16" GT and Outback wheels are a common upgrade and fit all models. 17" wheels can and have been put on these models, both from US and overseas models.
Basically, any Subaru Legacy, Impreza, Forester or Outback wheel is interchangeable. They've used the same lug pattern since the first Legacy was introduced in 1990. Only the 2005 STI WRX breaks this rule.
You can have the best suspension in the world, one of those Prodrive/Eibach, TEIN or CUSCO setups, but if you don't have the tires, you can't keep the car going where you want it to, or stopped. Treadlife and traction are the most important factors in choosing a tire. There are tires with marvelous traction that are wasted in 10k miles and they cost $150 each. You also don't want to get stuck in the snow with a set of el-cheapo tires that you got on sale a PepBoys for $29 each.
Pirelli, Dunlop, Bridgestone,Toyo, Falken and Kumho are all high quality and reasonably prices solutions. If you are in a climate that gets snow and rain for at least half the year, consider a good high performance all-season radial.
The Yokohama AVS Sport and Kumho Ecsta 712 are two very good tires to look for.
The Legacy Turbos came with significantly upgraded brakes when compared to the n/a versions. 10.9" x 0.9" vented discs up front and 10.5" x .07" in the rear.
Ever seen a 911 with those 14" cross-drilled rotors and 19" wheels? Yours won't look quite that good unless you want some of the STi 4-pots available for the newer Legacy and WRX models. Even the 11.4" WRX/Outback brakes are a marked improvement over the Turbo brakes. They don't have the tendency to warp the rotors as much either.
There are, of course, upgrades available. Better pads can make a noticeable difference, but larger cross-drilled rotors are the favorite of rally cars and serious auto-x racers. Most of the venors on the Links page have at least one upgrade available.
Any brake upgrade that fill fit an Impreza, or any stock Subaru brakes will fit the Legacy. I have WRX front brakes on my Turbo right now and they installed without issue. The most important thing to consider is the size of the wheel in diameter and its offset.
If your car has more than 60k miles and you haven't replaced the struts yet, put it near the top of your list. If you have driven a new Legacy GT or 2.5RS and then jumped back into your car you might have noticed that it feels a little more squishy than that new car. It might not stick around that corner as well and the body probably rolls a little more and the wheels whine or sqeal without really being provoked.
Most vendors now sell the KYB AGX adjustable struts for the Impreza and Legacy, while the GR2 is a nice OE replacement without the adjustability. These are assured to make your car feel and turn much crisper. The Eibach springs will also lower your Legacy about 3/4 inch and make the wheels fit in the wells a bit better. Whiteline, out of Australia, makes some very nice springs with a very slight lowering effect. They even have a wagon-specific spring available.
The rear sway bar on the Turbo is 18mm from the factory so not much has to be done in this area. Most non-Turbo Legacys have 16mm rear sway bars and 19mm fronts.
Basically any suspension that will fit on a 93-01 Impreza will also fit on a Legacy Turbo. I'm using coilovers meant for an Impreza. TEIN, CUSCO, GAB, DMS and LEDA will all fit on a Legacy.
Be careful about rear sway bars. The Impreza ones will not fit on our cars. Purchase one specifically for the Legacy, as it must clear the spare tire storage well in the back.
For Turbo cars, there really aren't any options other than a replacement K&N filter, short of having a custom intake made, Removing the "snorkus" from inside the fender should help airflow slightly, and make a little more noise. I have a prototype turbo-out intake that was made by JC Sports, but they've subsequently dropped out of the market for all intents and purposes. Some BBS members have modified an aluminum or plastic coffee mug in order to remove the resonance chamber between the airbox and turbo inlet. This should smooth airflow into the turbo.
Normally aspirated models have about the same options, a replacement filter is pretty much all that's available. Most of the newer models use revised intake tracts, and designs meant for them aren't a direct attachment. A few companies, Weapon R, Injen and Cobb, may have intakes that fit newer models easily, and may be adaptable to older ones.
Intercooler on a 91-94 Turbo
Since a turbo is a compressor, and compression adds energy to a gas, heat is also given to the gas from both the compression and the hot metal impeller/compressor as well as the other compenents of the intake.
The easiest way to remove heat from the intake is to install an intercooler. The simplest intercooler is just a box with metal fins and pipes from one end to another, in the same kind of design as a radiator but for air. As the air passes over the box it takes away heat from the box. This cools the box and allows it to absorb heat from the internal air. This basic system can add horsepower and improve combustion. It's imperative to have an intercooler when increasing boost.
Matt has one on his 91 sedan. It's from a 93-96 WRX and installed relatively easy, for something that wasn't meant to be there. I'll have more details when he updates me on the process. My own experiences with air and water intercooler installs, however, were admittedly short-lived. Without a moderate amount of custom work, the intercoolers don't fit that well.
Boost on a 91-94 Turbo
More specifically, more of it!
The whole principal behind a turbo motor is to use escaping exhaust gas to force air into the engine. This, coupled with more fuel, creates more horsepower. The more pressure allowed into the engine, the better. Obviously there are limits to this and that's why your stock Legacy is limited to around 8.7PSI.
A Wastegate activates at around 8.7PSI to bleed off the excess pressure and make sure you don't blow up your engine. This limit exists in all turbo and supercharged engines in some form, whether higher or lower.
You must understand that your car was built to go 100K+ miles with no service to the turbo unit and joe-schmo at the wheel. With good premium fuel and an intercooler, 11-12PSI is relatively safe with the aid of a boost controller and gauge.
Hallman makes the most inexpensive and uncomplicated controllers around. We'll have more information in the future, as Shik currently used one of these.
IThe Apex-i AVC-R is one of the best standalone electronic boost controllers available. It's an expensive, but impressive boost and engine information computer. It has monitoring for boost, speed, RPMs, Injector duty, Solenoid duty and throttle position. It lets you adjust variable duty settings for two seperate boost setting levels. It's very complex unit but extremely powerful.