For the kind of racing most of us do, preserving a little bit of low end is important. But our engines specifically have a decent amount of low-end torque (unlike most Honda engines - hehe) so the backpressure lost from removal/gutting of the cat is of little consequence. You might notice it, but it won't harm the overall performance too much. If you go catback, just make sure you stay under 2.5" piping (with the exception of turbo-ed cars), otherwise you lose exhaust velocity, then your low end is gone entirely.