i do all my own work too, and did alot of research on exhaust before i purchased it. The long tubes i bought do not let the trans drop but kooks, american racing, and a couple of others allow the trans to drop out. From all of the info i gathered, long tubes are the way to go if your going to do it. The stockers will flow up to 650 hp, so it isnt all that necessary, but im going to do a a blower eventually, and a small shot of nitrous before that, so longtubes was the way to go for me. Ill try to get a coulple of threads about longtubes vs shoties and send you the links. p.s....the reason some people claim a higher gain could be because they swapped out a mid pipe, or did full exhaust. most people dont swap out the stockers for shorties and leave the rest alone. Some people claim a higher gain than that also, that was just one or 2 cases i heard of. what i was talking about was just swapping out the shorties for the stockers, if the rest of the exhaust was already done, the gains would not be that great.