hey, i made a mistake & ordered the wrong size mufflers for my truck. i had to get it out of my shop & get home, and since i had already cut out the stock muffler (read very friggin heavy!) i took a 2 1/2 balance tube kit & 2 1/2 exhaust pipe & made a temp pipe patch to replace where the muffler was at & put in a balance pipe at the same time. ALL OF THE RESTRICTION IN THAT SYSTEM IN THE 4 FREAKIN CATS! my truck sounds awesome with no muffler & once i cut out the secondary cats i will weld in a set of borla 2 1/2" muffs. but now i can get 3rd gear chirps. it helped a ton!