Since its introduction to the U.S. in 2002, the Subaru Impreza WRX has been one of the most popular tuner cars in the country. With a four-cylinder turbocharged engine, all-wheel-drive drivetrain, ample interior space, and a sub-$25,000 price tag, it's easy to see why the WRX became a popular choice among performance enthusiasts.

Early attempts to increase power output often ended in catastrophe. Simply slapping on a manual boost controller and pushing 20-plus psi on otherwise stock cars resulted in many blown motors and shattered transmissions, but as some of the top tuners gained experience with the car, new products hit the market and the power threshold rose. Now, 700-plus wheel horsepower is no longer a pipe dream but a reality.

This buyer's guide showcases some of the very best products from the most respected manufacturers in Subaru performance. It encompasses a wide range of products to satisfy the needs of any enthusiast. We've also included a section called "Under $200" where we showcase products that are essential for any buildup without having to break the bank. Whether you're building an Evo-slaying, quarter-mile monster or a daily driven, weekend road race car, we have what you're looking for. Enjoy!