I've read on here about KEM and spartan tunes that are pretty damn good on the 08's. Do a search for it, you'll find all you need to know. Gets awesome power, and mileage increases to almost 18-20 on the highway. It involved a dpf delete pipe, and turns off regen. Voids the warranty though.
I have just over 6k miles on mine and I was at about 12-13mpg city and some highway here and there, but now I get around 14.5mpg with dpf delete and extreme tune loaded. But then again I'm also driving like an a$$ at least for now because I'm having so much fun with the added power. I'm sure it will pass, but for now :burnout :woot:
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