Hey, I have a 91 Z28 Convertible. It has a 5 speed. It's pretty much stock except for a Flowmaster 3" catback. Anyway, what's the next mod I should do? I was thinking headers, but which ones? Also, any idea what my car should be running right now?

 

I'd say mid-high 15s in good running condition, please read the sticky post on this page, and it should answer all your header questions. I'd look into some Hooker shorty headers.