My brother, father, & I installed a set of Edelbrock Tes headers & y-pipe combo on my truck today. Definately a difference in power. The engine revs alot faster & smoother. I ran a 2.5" exhaust too. No cat & a Summit muffler. For $15 this muffler was well worth it. It has a very deep tone without being obnoxiously loud. I can't wait till I get it broken in. Maybe tomorrow I'll get to run it & post some new times.