Here's a question some friends of mine have been kicking around. When overhauling your exhaust for any car (my car is a 98 Accord 4cyl), is it better to start with a cat-back system, replace the catalytic converter, then swap headers; or do it the other way around, headers to catalytic converter to cat-back? This is assuming that your system has been well planned out and your not just slapping "performance" parts on that might not play well together.

 

If you are speaking in terms of performance gain, starting with the cat-back will probably be best. Here's why - if you start at the header you still have a restrictive exhaust behind it.

This is a big generalization without knowing which of the stock peices is the most restrictive. If you knew that, that's where you'd want to start.

My $.02