still if thats not the only thing ur gonna do, that would still be a big waste of money for just the exhaust. i have a catted h-pipe for the same reason as u and basically i have the exact set up ur going for. but i got all that done for less than half what u paid. and my install was 80$ i got all my parts for about 300$. ive read a lot and long tubes wont do anything for u, big waste of money, and most ppl say get them last if u really wanna do another mod when ur done.
ps, the h-pipe and 40s sound real good u wont be disappointed