I have an 06 gmc with the lbz motor, and I'm running the power pup programer on the performance level with an AFE stage 2 intake. I have stock exhaust system less the muffler. I am thinking of running a 4in down pipe to the cat and a 5in from the cat back. Has anyone tried this? Would it benefit to do this? I know about adding a finger stick and the egr blocker plate just didnt want to cut into my wiring.