Well I am getting the GMK CAI, have optimized the TB, and now I need to get that air out quicker as well. Exhaust looks and sounds cool, but doesn't offer the performance per dollar that I am looking for now. So I want headers next. Obviously gutting the precats will help a bunch, but how much will it help compared to just buying headers? The existing manifolds, headers, y-pipe, and precats look pretty freeflowing if I could get rid of all the crap in the precats. So my question is how much difference is there between $660 MSDS headers and gutting the precats for free?