So I guess its time to add to the group. I have a GMC reg cab SWB 4X4 that is now sporting the guts and drivetrain from a 2013 Silverado L9H, NHT truck. This is the truck that GM should have built. Its been a bit of a project and not quite done as I'm having a few CEL/Airbag lights but I have good friends with the right equipment to address those issues. Just waiting for the weather to get better. Was able to utilize all of the factory exhaust from the L9H minus the muffler, was a bit too long so I had a local shop put in a Dynomax bullet. Sounds pretty good and not too much louder than stock.