Well I had just pulled off the front header and crossover from these SD headers I have. I.D. measured 2.0" on the crossover and only 1.5" on the primaries...I am pretty sure some gains are to be made going to a 2.25" crossover minimum and 1.75" primaries at my current mod level. My demands may be a bit much but when you start comparing things that aren't alike without even mentioning one example on another car of how my current headers can capably support my setup I get testy. I know he was just trying to help but this is a WTB thread. I would gladly spend my $ on some used bigger tube headers.