How much improvement would you see if you cut the muffler off of a 03 duramax that is factory. Would it be a noticable amount or not worth the time.

Power? Not enough to worry about. EGT reduction though. It definatly wont hurt anything. Just take a bit of time and just a few $.

i could tell a diff.

you will notice a small gain in throttle response and mpg and a huge drop in egt. Do it.

Cutting of the muff Will it make the turbo more noticable without the muff and what is the different mpg difference if any.

Has anybody replaced the rear u-joint in an 03 d-max if so how much of a pain was it and what is the price of the u-joint usually run.