Yeah mine has a venom cat, running 14psi till the end Ratter explained to me that the stock exhaust is good, but it still causes back pressure and can then start to effect the valves (as I still have stock springs) He said valve spring upgrade would be able to get more power or put a more free flowing exhaust on Every car is different, mine also has 120,000k's on it Here's a dyno sheet if anyone curious