Originally Posted by UFO

Nope, no difference at all after adding the Perrin 3" cat back. In fact, the car ran 1/10 slower in the 1/4 although the temp difference was about 50 degrees between runs . Added the DC Sports down pipe/cat delete and, you guessed it, still didn't notice a difference. The bad thing about the DP was the loss of the kick you in the back feel when boost hits.