I would use a little copper spray as Les suggested. I use blue locktite as well....but the main thing is take your time to line up the gaskets and torguing them down.... I didn't have a lot problem with the y-pipe, but you want a good seal, and they do move around until you get the t clamps tightened. You want to keep an eye on them as well...and recheck them after you put a few miles on her....I have had more problems with boost leaks there until I finally got them tight and right....let us know what you think, even with out the retune....lol I was surprised how much more low end they create....