Originally Posted by DeusExMaxima

I discussed this a bit in the exhaust thread I started for teh development of the Cattman exhaust system. Brian and I dropped the stock exhaust to examine it. We bounced ideas back and forth as to why Nissan crimped the pipes so much. The initial appearance is to clear the chassis. However, I dont believe thats what it is. Nissan regulates the output of the VQ35 motors to where they vary in hp output from 240 to 298. It is very easy to do my crimping the exhaust but make it appear to be for the purpose of clearing the chassis. When I was at the Stillen open house, they were installing exhausts in the G and Z cars. I saw the stock exhaust for those cars and they had the appearance of aftermarket because I did not see any crimps in those pipes. Anyway, thats my guess, I beleive I am right. I also beleive a properly designed cat back exhaust coupled with a y pipe should get about 20 hp because of the obvious severe restrictions. Also, aftermarket Gs and Zs dont gain much from cat backs because the exhaust for those cars are already decent.