ok, i've posted a similar question in the GTO forum, but there seems to be more exhaust talk on here, so i will ask here and maybe get more feedback...i have an LS1 2004 GTO...it had the weak-looking rear fascia where both pipes came out the same side...so i purchased a 2005 rear fascia with insert to split them out...now my idea was to leave the stock manifold, delete the cats, and run an LS2 dual catback system aftermarket (prob slp loudmouth or magnaflow, not sure yet)...my question is, will there be any probs goin from the stock manifold for an LS1 to the aftermarket for LS2? are lengths and diameters the same? plus any feedback on which exhaust options to go for would be greatly appreciated, just starting this project...