I have a 33 GTR with a stock exhaust. It's pretty awful. it's very tiny, heavy and restrictive. It's one of the things nissan used in order to keep the power under the 206kw agreement. They were quite smart though. They used reasonable dumps, pretty good front pipes (on GTR) and a good cat, then put a strangling exhaust on it, becuase of this a modifier can reap a much bigger than normal gain when changing cat back exhaust on a GTR. thanks nissan