hey how ya doin Ive got an 06 quad cab and i just took the muffler and tailpipe off and bought a 2 ft chrome 5 inch stack for a big truck a 5inch to 4 inch reducer and a 5 inch guilitene clamp. it has a really good tone to it it does not sound loud and obnoxiousit turns down right in front of the rear at cruising speeds its nice and quiet but it will bark at you if you roll in the throtle. I did notice a significant gain in turbo spool up as well as fuel mileage. When I first got the truck I was averaging 15. 5 to 16. Now I average 18. 5-19. 5 mpg