I have a 2001 cobra with a american thunder c/b (2 chamber). I was wanting to get a new mid-pipe and am torn between an X or an h pipe. I will prolly have to go with the catted pipe b/c of emissions, but if i really need to i will change it out every year for emissions. what is the differece in sound and power increase with my c/b? any help would be appreciated. thank you.:shrug: