The 2008 STI is one of my favorite body styles. The wagon shape has an aggressive stance and they really uped the interior from the original 2002 WRX that I owned. There are many differences with the car as far as the power mods go with tuning compared to the earlier model. However the basic engine is the same as the 2007 with some minor changes like the MAF sensor. When we first started working on our Project 2008 WRX back in 2007, we were able to really start building some quality products through Agency Power.
One of our long time friends and customers recently picked up this silver 2008 Subaru STI and we began modding it for him. Some of the initial build parts were done to improve the suspension. This car was purchased to assault the mountain roads on a snowboard trip. First we upgraded the shocks with the Cusco Zero2E Coilovers. To keep the chassis handling well, we added our Agency Power Front and Rear Adjustable Sway Bars. Then to give it that one more step of awesomeness, we put on the beefy Agency Power Rear Adjustable Control Arms. Finally, since we are adding some of the Agency Power StrideSeven Wheels in 18×8.5 on the car, we had the calipers painted from black to Silver and added the STI logo.
Now that the handling was dialed, it was time to beef up the power in the car. The first step was do to the modifications in stages which we could analyze the performance. Our first stage was to do the Agency Power Cold Air Intake and the COBB AccessPort Flash. Once we tested this setup, we then added the Agency Power Blow Off Valve and Agency Power Catback Exhaust. The BOV is designed the same way the 2007 STI was and works either in 50/50 or 100% mode. We opted to keep it at a 50/50 setup. The catback exhaust is all 3inch stainless steel and features titanium tips. The catback alone added about 10 horsepower. Our final stage to upgrade the power was to add the catless downpipe to make it a complete turboback exhaust system. The downpipe would help the exhaust flow much better making the total horsepower gain from the exhaust 20 horsepower. With the bellmouth downpipe, there is not restriction in how the exhaust gas flows. In addition, we prototyped a new Front Mount Intercooler which keeps the stock fog lights and water bottle resevoir and minimizes cutting. Once this was bolted on, the entire car was retuned with the COBB Accessport for some impressive numbers. In the end, the car put down 296 awhp and 313ft/lbs of torque on our Mustang Dyno. Quite impressive while still on the stock turbo. Compare this to our 2007 Project STI with similar mods.