Progress Technology
Antisway bars
The Progress Group developed new front and rear antiroll bars for the '02-'06 WRX and STI. Both antiroll bars are 22mm solid steel bars. The front bar has two holes of adjustability while the rear has three positions. The bars are designed for use with the OEM endlinks. The kits include all hardware needed, like new drop-down brackets, low-deflection polyurethane bushings, new bushing brackets, and synthetic grease. This new antiroll bar system will improve steering response and minimize body roll while cornering. All Progress antiroll bars are manufactured in-house and feature cold-formed bars and precision MIG-welded ends.
MSRP: $145.35 (front)
$182.75 (rear)

Competition Sway Bar Set
This hard-core Competition sway bar set from Hotchkis offers the same great benefits as the company's sport sway bars but utilizes a more aggressive rear bar set that works better with racing tires and helps create slight oversteer in autocross, slalom, and road race scenarios.
MSRP: $671

Competition Clutch
Subaru Flywheels
Competition Clutch offers a wide range of flywheels for the Subaru family, including applications for the WRX, STI, Impreza, and Legacy. These flywheels are one-piece 4140 forged steel and come in lightweight and ultra-lightweight versions, and are suitable for street, track, or rally racing. These flywheels are compatible with any clutch kit on the market and are SFI 1.5 approved.
MSRP: $279-$399

Perrin Performance
Positive Steering Response System (PSRS)
The PSRS increases steering response in corners by adding additional caster angle and straight-line performance, preventing lift when accelerating. It installs easily by eliminating the squishy factory rubber mounts.
MSRP: $299.99

Agency Power
Rear Adjustable Control Arms
Subaru WRX STI '08 And Newer
Agency Power developed these rear double adjustable control arms for the '08 and newer Subaru WRX or STI. The rear control arms fit both the GH (wagon) and GE (sedan) chassis. The control arms offer the ability to give your vehicle proper camber adjustments. Its stout build adds rigidity and, coupled with their other suspension components, gives you the ultimate track setup.
MSRP: $650

Tanabe Racing Development
DF210 lowering spring
'05-'07 STI, '08 and newer STI
The DF210 performance spring from Tanabe offers the lowest dropout of all of their springs, and is a good balance of looks, performance, and comfort. Spring rate is raised 10-15 percent to compensate for shorter suspension travel, but is soft enough to ride very comfortably.
MSRP: '05-'07 $260
'08 and newer $290

B&G Suspension Systems
S2 Lowering Springs
B&G Suspension Systems offers its S2 lowering springs for the '04-'07 Subaru WRX. The S2 springs lower the vehicle approximately 1.4 inches in the front and rear and feature a limited lifetime warranty.
MSRP: $309

Tanabe Racing
Development USA
GF210 Lowering Spring
'04-'07 WRX/STI And '08 And Newer WRX/STI
For the highest and most reliable performance from a performance spring, the GF210 is an excellent solution for cornering enthusiasts. The stance of GF210-equipped vehicles is aggressive and is but one indicator of the engineering and weight-balance tuning that goes into these springs. The spring rate is raised an amazing 30-40 percent over stock, but with careful consideration in keeping within specs of the valving of most stock and aftermarket shock absorbers for maximum suspension longevity.
MSRP: '04 $260
'05-'07 $280
'08 and newer $310