Have the long tubes, y pipe and loudmouth. Don't remember the y pipe number. I also have the drive shaft loop. All are SLP. No clearance problems with the factory piece. Just make sure it's spaced away before tightening clamps.
LorcinLS1.....Thanks for the input..... The SLP y-pipe (31035) I'm looking at, as it appears to be the only one that connects to stock cats. Keeping the front half stock (manifolds and cats). I'm looking at getting a new cat-back, and also figured to get rid of that oem restrictive y-pipe while I'm at it.