So I noticed my stock sedan Y-pipe was making a rattle noise from within the pipe and I ended up picking up a Q60/G37 Coupe Y-Pipe and swapping it out.

During this process, I realized the inlets where they hook up into the cats are smaller than the sedan.

Am I going to have any problems? I think I did manage to eliminate the noise coming from the Y-pipe but I'm curious about the inlets and if they are going to cause any problems other than restricting some exhaust flow.

Thoughts?