None other than looks. CAI will give you more whistle sound & seems to be a little quicker on low end but no measureable mpg gains. You'll need more air only if you tune mid to higher tunes. Now, this is only my opinion. There are millions.....
The muffler y'all are talking about is small, full opening, so exhaust flows through it with ZERO restriction. The only reasons to get rid of the tail assembly is to get a larger diameter exit with less severe bends or for looks.
You should just get a FULL exhuast and keep the stock tip like willie! No one will ever know your packin 550 HP (get a spartan too) and once you see the look on someones face you'll never go back! :woot:
A forum community dedicated to Diesel engine owners and enthusiasts. Come join the discussion about performance, builds, ecodiesel, towing capacity, modifications, classifieds, troubleshooting, maintenance, and more!