i'm running the thermal r&d with a powercore race cat (basically a test pipe). the cat gave better throttle response and it made the exhaust louder, especially when vtec kicks in. i paid $150 for mine including shipping and it even came with the bung for an o2. of course i got cel 67 so i had to put in a o2sim. but the pipe is polished stainless and comes with gasket and hardware.