Since its introduction to U.S. shores, the Subaru Impreza WRX has proven itself to a popular choice among import performance enthusiasts. With a base price of $24,495, the 2006 Subaru Impreza WRX may just be the best performance car value under the $25K mark. For 2006 models, you may first notice that Subaru has performed a minor body change update. Fortunately the improvements for 2006 are beyond skin deep. Subaru has sweetened the performance pot with a powerplant upgrade to a 2.5-liter engine. Factory "underrated" at 230 flywheel horsepower, our testing found that the power delivered is more on par with an engine generating 240 flywheel horsepower. In fact our baseline power was 10 wheel horsepower higher than the 2004 WRX that we tested. Why would Subaru purposely underrate the WRX's output? The answer is simple. More consumers would be willing to shell out the additional $8,500 premium for an STi, if the power difference is 70 horsepower instead of 60 horsepower. From our perspective, the WRX and STi are great platforms for anyone looking for an extremely versatile and capable street performance vehicle. The WRXs value is immense and we appreciate that one manufacturer is offering an all-wheel-drive, performance platform under the $25,000 mark.

Challenging Changes

One change with the 2006 WRX that we were not happy to see is the switch to an electronically-controlled throttle. Vehicles that are "throttle-by-wire" tend to give the aftermarket additional headaches. Since no manufacturer has been willing to offer a plug-and-play engine management system for an electronically-controlled throttle vehicle, most tuners have been forced to use piggyback and ECU re-flashes instead. Fortunately, we believe it's only a matter of time before a standalone solution will be available.

Keeping it Simple

Anytime a manufacturer changes an engine or ECU setup, the tuning community is forced to treat the platform as an entirely different car. Not knowing what new pitfalls may be present in the 2006 WRX, we decided to ease into our buildup slowly. Sticking to the basics, we opted for an intake and cat-back exhaust.

As for the intake, we decided to try out a new company. Fujita Air of Temecula, California has recently hit the intake market with an extensive application list. We kept installation time to a minimum by selecting the short-ram intake. The Fujita Air intake used premium components in its construction. The polished aluminum intake was manufactured from 6061-T6 aluminum and teamed with high-quality Hose Techniques Silicone/Nomex couplings. All the hardware was also included. One of the unique features of this intake was the packaging. The intake was packaged in a Fujita Air duffle bag and a Fujita Air hat was also included. According to Fujita Air, every single air intake system is developed with the use of extensive chassis dyno work.

For the exhaust, we selected an N1 exhaust from A'PEX Integration. The muffler section features a 115mm adjustable tip that allows a perfect fit with factory or aftermarket rear bumpers. For this application, the piping diameter starts at 65mm to mate to the catalytic converter before expanding to 80mm on the way to the muffler.

The Dyno

Strapped to a Dynamic Test Systems 4-wheel dynamometer, the stock 2006 WRX generated 206.0 horsepower at the wheels. In case you are wondering, our 2004 Subaru WRX generated 196.6 horsepower while our 2004 Project STi generated 264.4 horsepower on the same dyno all in bone-stock configuration.

The Fujita Air short-ram intake delivered some significant power gains. Power was increased at nearly all points in the graph. Peak horsepower rose by 6.3 horsepower. This took our peak wheel horsepower figure to 212.3 horsepower.

With significant power increases resulting from the Fujita Air intake, we were interested in seeing what gains the A'PEX Integration N1 ExTi exhaust would deliver. The A'PEX N1 exhaust delivered across the board, making more power at every rpm. The most significant gains came at 3500rpm and carried all the way to redline. Peak horsepower rose by nearly 10 horsepower. The end result was 221.7 horsepower at the wheels.

One of the most interesting facts is that this 2006 WRX saw the same wheel horsepower improvement from the intake and exhaust as our 2004 tester. Both showed an improvement of 15 horsepower at the wheels. To the credit of the 2006 version, it started with a 10 wheel horsepower advantage.

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