it wont really improve your milage only because it wont full activate when your almost in full boost. It does lower egts down. So if your towing alot then it totally worth it. My egts at wot never get above 950ish. Normal is like 1100-1200 i think. I run a 40%meth mix and i can fell a big difference power wise. Like a 75 shot of nitrous in a car