As for the exhaust, when we first started the whole thing was short like 3-5"! They ended up cutting off the muffler from the rear where the piping starts out and adding extentions. Also the flange where the axle back piping attaches to the mid pipes had to be redone in order to fit. The hangers were extra long as well on the muffler, they were cut as well. All of the GREddy piping was used, some of it was extended. Nothing extremely hard to do.
I have it on my car, iono if mine was a bad batch or what, but the y-pipe was not bent correctly so it was hitting the sway bar bracket when installed. Had to take it to an exhaust shop to get the pipe bent down, costed me $20(not bad imo) but otherwise no complaints about the exhaust, sounds nice, not too loud