what kind of fuel milage increase can i get off gettin a straight 5" exhaust, and a good high flow intake, what else can i do to help my milage?

 

I'm not so sure on how much of a gain in MPG you will notice in regards to exhaust. Exhaust will bring down your EGT's a good amount though. And a good intake will probably help a bit, again not sure on the exact amount.

I would recommend some sort of chip for better fuel mileage. I have the XZT+ installed in my 99 and it helps quite a bit when only on "timing".