The NPP exhaust sounds good but it seems that a lot of people are having issues with rattling and squeaking sounds after reading this thread:
http://www.camaro6.com/forums/showthread.php?t=443939
Some of the people are commenting that the NPP exhausts are doing the same thing after the dealership has put a brand new exhaust on the car. Personally, I would rather buy a non-NPP vehicle, buy the rear NPP fascia (paint it gloss black) and then put on a Corsa axle-back. Your probably looking at a cost of $1500-$1700 instead of $895 for the NPP exhaust--but you don't have to worry about warranty issues down the road or having rattling/squeaking sounds.