Mechanically not much really changed from the Impreza. A new interior and body shape, but under the skin it is not really new at all. The same reliable everything is still there. The rear suspension roll center has been raised slightly and the front castor increased. These were improvements discovered in the WRC98 Prodrive chassis and have found their way into the new body WRX. The stock car really needs only a set of good wheels and tires to become a very refined GT sports car. It becomes surefooted and has impeccable road handling manners for the average driver. 

Tires and wheels:

When selecting wheels be sure to insist on the proper offset. 7 inch rim needs 55-53mm, 7.5 50-48mm and 8 inch needs 45-48mm. Also check that the wheels spoke design will clear large calipers, as many designed do not and you are then limited to the stock front brakes. The new STI gold Brembo calipers only have two wheels that fit them. The special racing 17x7.5 GT-1 (not the standard ones) and the new 18x8 Turinni. Wheels for sale by SPD Tuning Service meet these requirements.

If you live in the snow zones, it is truly better to use your old wheels for winter performance tires, but noting that the 16x6.5 wheels do not clear the four piston caliper option. We recommend sport snow tires such as Michelin Pilot Alpin ,the Dunlop Winter M2 Sport or the excellent Bridgestone LM-22 in a 205/55-16. The stock Bridgestone M+S tires do not cut it on snow. Those of you who see lots of snow should go straight to the Nokian Hakapelitta 1 and possibly a 195/60-15 to clear chains if you cannot use studs. Noisy and studable, they are the best snow tires made. The "ice' grip type snow tires just do not last on dry pavement and do not really work that well on ice. Give me steel on ice any day. My advice is to just carry chains, if you cannot use studs. We try to avoid M+S tires for year round use, as they just do not show the chassis on dry or wet roads the way a good high performance tire will.

We recommend at least 17x7 wheels and 215/45-17 tires. Most owners use 225/45-17.  SPD Tuning is shifting to 17x7,5 and 18x8 rims. We use 225x40-17 or 225x40-18 tires. Ultra performance for the 4-door body is to use a 235x35-18 tire. For standards of comparison the Bridgestone S-03 seems to have the high ground these days for dual track and road use. We still recommend the Toyo Proxes T-1s as a excellent wet and dry performer. It is highly recommended for those areas of the country that see a lot of rain. Quite extraordinary in the wet. I still like the Pirelli PZero, a totally dry road performance tire that is equally at home on the track when the tread is in its last third of wear. especially with the extremely high track surface temperatures we seen in the southwest.

Suspension:

The stock suspension should not be changed until you drive the car on good performance tires. For many, 225 performance tires will be all the modification desired. As a sport suspension we strongly recommend the STI 40mm shock and spring kit. It retains an excellent ride quality and has much improved cornering power. There is no need for coil over suspension on a good road going sport setup with this STI kit availible. On a budget, we have the lower, slightly stiffer Eibach spring kit i stock as well.

The 4-door WRX now has 19mm front and 20mm rear anti-roll bars.  We recommend changing the 18m bar fitted to the 5-door be swapped out with the SPD 20mm bar. We remain politely ambivalent towards fitting the car with larger anti-roll bars. They are a convenient way to reduce body roll in corners with mild spring rates, but ultimately make the car a bit harder to control at the edge of traction. It is not an accident that we use 17mm front and 18, 19, or 20mm rear bars on our gravel suspension Group N rally cars instead of larger bars. On smooth track big bars and big springs are effective, but with milder spring rates and the possibility of driving on mixed or rough road surfaces I still prefer to run more spring and standard bars. The car has a smoother transition into corners, reducing the chance of spinning the car. The chassis will respond much too quickly for my taste at the limit with larger bars and mild spring rates, and the car will have much better traction off corners with reasonable bar sizes. I do not deny the larger bar setup's popularity. Just come follow me into a rough, lumpy corner some time. I can drive to the edge with much greater confidence. The lighter bar combination gives more stability and control under braking and will pull off the corner with better traction.

For those wanting greatly improved cornering power we currently offer two DMS suspension coil-over kits. The DMS company has great success in rally racing world wide. As you know, rally racing setups are as close to street performance needs of any type of racing. The smaller, 40mm inverted strut setup is purely a road going sport suspension just one notch better than the STI 40mm inverted kit. It is better by the fact that the shocks are adjustable for stiffness and offer the advantage of a lower ride height by 35mm. Contrary to popular belief, coil-overs are not used to raise or lower the car but over a very narrow designed ride height. What is most advantageous is the ability to corner weight the car and adjust the weight evenly on all four corners. The improvement in braking stability is uncanny. I would not consider the 40mm DMS to be quite a track day setup when we compare it to the 50mm DMS kit.

The 50m DMS is possibly one of the finest kits availible for a road/track WRX. The rally version of this kit is highly completive in any rally short of WRC level where $10.000 suspensions are being used. The large 'aircraft landing gear' 50mm strut diameter contains independably adjustable compression and rebound rates perfectly tailored to the WRX. It uses progressive spring rates with rally proven gravel spring rates, an excellent compromise for a dual purpose road and track car. It is availible with full track spring rates.

Aside from the performance of the 50mm DMS is its build quality. Made on new CNC machines with superior tolerance control. The fit and finish are best quality possible. They are completely rebuildable and offer the option to include any advances in valving  that may be availible. The camber control is via shims in the rear with a standard 2 degree negative setting. The front are built with a 1.5 to 3 degree adjustment using the stock hub attachment eccentric bolts. Due to the physical size of the DMS it is sometimes necessary to space the rear wheel 5mm with some wheels. I cannot over stress the advantage of the 50mm design for action of the internal valves. The 50mm DMS are the real deal when it comes to dual purpose road/track suspension.

SPD Tuning has an exclusive needle bearing supported mono-ball front top mount to permit quick adjustment of front camber for track sessions where 1 to 2 digress camber may be desirable. This indexed top mount makes it easy to use one setting for street and another for track. The rear of the 40mm and 50mm DMS use a modified Group N Subaru top mount, as the shim adjustment at the hub has proven quicker than an adjustable rear top mount. Rear camber does not get often get adjusted because rear camber's main function is to control handling balance in the last third of a corner. An area where the 2 to 2.5 degree number has proven most effective in a dual use car over time. We are always searching for more front traction and fiddling with rear camber is not the place to look! SPD always will work closely with your regarding set up tips for coil-over kits.

For basic road use with non-coil over suspension we want to get as much negative camber as the front adjustors will allow and set the front toe to zero scrub, usually zero to 1/16 toe-out. We just make sure the rear is to factory settings. Contact us for more aggressive alignment settings as they depend on your tires, suspension and expected use. Determining suspension needs always require a bit of back and forth dialog so that we meet your expectations AND budget.