...ah, very nice. Exhaust is a bit louder (love it!) and the response is definitely there. I haven't done HIGH RPM (felt like hitting fuel cut around 6500K) to see if that part of performance has improved, but I'm pretty sure it will. I had some mild hesitations through the RPM range with the old cats -- can't feel the hesitations anymore.
I told Greg that feeling/hearing the Cat-Pipes in made me feel like I was in the pipe riding the wave : ) Z's make you imagine odd things : )