Ever since I had my ypipe and muffler put on, it seems that the whole exhaust system from the ypipe on back is looser than it was. There is an awful lot of movement in the catback when I push on the muffler. The shop welded the muffler to the previous mounts but I'm thinking I should go back and have them mount it tighter to the underbody. Should you be able to wiggle your muffler around easily? I also notice a few rattling noises when driving and sometimes the exhuast smells pretty bad after I've been driving a while. It kind of smells like a mid 90's v8 chevy or something. The sound is real nice though! I just have to get this corrected or it will drive me crazy.