Turbo back is a must for improvements, I did 4" turbo back Summit exhaust, I did not want to spend a ton on exhast with a 250,00 m iles truck that I drive all winter, they all pretty much perform the same, just some look nicer, I added the stainless 5" tip for looks, usually you will not notice much until it is chipped.
I love the sound...280,000 miles now and ran 15.1 so far overboosting map sensor...99 7.3... love my truck!