Just got my duel magnaflow's. The guy that put them on said I should come back in a day or two so he can check the bolts after they cool to make sure they didnt come loose. He also said I can do it myself. The question is when I went to tighten them some were loose and some were set. Should I tighten all of them tight or should they not be really snug.

 

They should be good and snug. They should not be loose at all. What I do is put the rachet on them, and then put 3 fingers on the end of the ratchet and turn it to the point where i cant go any farther without putting my whole hand on it.

You dont want them loose because that can cause exhaust leaks.