nice info. damn, I pretty much just bought my dc 4-1's. now i find out that they are not that good. well, guess i gotta save some more. anyone have advise on a good cat and exhaust combo if i go with a good header w/ 2.5 collector? I would search on this but that led me to the rsr exmag which was just dogged on so i figure preferred pieces differ every little while.