The Subaru WRX has tremendous performance out of the box. The latest version (this is 2012 model year) has 265 horsepower. And the STI model has 305 hp! The STI can do 0-60 in 4.9 seconds, and runs a 13.3-second quarter mile, according to Road & Track magazine. Not bad, but...can it be improved? Of course! When we say WRX performance, we don't mean STOCK performance.
With simple bolt-on parts (bolt-on meaning you don't have to take apart the actual block or heads), we can increase the horsepower of the WRX (either standard or STI) to over 400. This will make the car faster than nearly anything on the road. Of course, remember that the car is a complete system. Upgrade the engine alone, and your suspension and brakes will begin to feel woefully inadequate. Upgrade engine and suspension, but neglect brakes, and you can imagine where you might end up.
Even engine modifications have to work together. Bolt on a giant turbo, and your stock fuel injectors and fuel pump won't be able to keep up. Fix that, and the intercooler that was great for the stock turbo won't be able to handle the increased heat load. And so it goes.
We suggest to our customers that they do modifications incrementally. It may sound appealing to just plunk down a pile of money for a whole bushel of mods all in one shot, but you may not like the car you've created. Doing modifications in steps allows you to get a feel for how it will be to live with the car in its modified state, and allows you to reverse a mod if it doesn't suit your needs.
For more specific modification info, see our Going Faster, Turning Better, and Stopping Shorter sections. Follow the links below, too, for some background and general hints on modifying your Subaru.
For specific parts to look at first, take a look at the Exhaust, Suspension, and Intake sections. Almost all our customers do some kind of exhaust modifications, and lowering springs are one of our most popular products. Higher-flowing intakes are another affordable and effective modification, and a favorite with our customers.