Borla's "Aggressive" catback exhaust for the WRX & STI features 2.5" diameter piping, no resonators, and a straight through muffler for improved performance and sound for mildly modified & stock cars. This exhaust is designed to mate perfectly to a stock downpipe, and, unlike the Hush and XR-1, cannot be upgraded with the 3" adapter so keep this in mind; if you're planning on changing out the stock downpipe for a full 3" piece, it will be difficult to mate this exhaust to it.

This system is designed for the end-user that wants some more sound and power but isn't planning on heavily modifying their WRX or STI. This system is stainless steel and backed by Borla's million-mile warranty.