I do have to agree with Morbius I love my truck but I hate the whole thick black smoke that a diesel puts out when on a road or highway. Racing or pulling competitions, is another thing.
But anyway your exhaust will not be that load if you have a nice free flow muffler. I have a 4 inch turbo back with a very nice MBRP free flow muffler and it sounds very throaty and it sounds like it is breathing very nicely but it is not over bearing and loud. Not any louder than those jacka**es that have those rice burner mufflers on thier little hondas. those things ARE loud and annoying! The only thing is when I turn on my exhaust brake and I am idling or sitting at a light i sound like a jet engine. Which I think is kinda cool. If you do the whole exhaust make sure you incorperate a nice cold air intake with it. I prefer a dry filter to the oil filter. I went with an S&B cold air intake. easy to install and you can really hear the turbo spin up now too. Good luck with whatever you decide!

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08 6.7L engine NOT STOCK, 6 speed auto, 2 inch leveling kit with 285/70/17 Toyo Open Country AT, 3.73 rear end, SLT package, 22MPG@70MPH , RBP fuel additive.