I want to know, if Im making 400-450 wheel horsepower, in a moderate state of tune (after turbo, I/C upgrade, etc etc, engine management) In a conservative state of tune, with mostly commuting being done with the car and rarely being WOT or raced, how much mileage can I squeek out of it.......? Just curious, Im not out for the highest numbers, but if I have to replace a head gasket to get 50k on a 400whp motor, thats easy....just wanna know what you guys making bigger numbers think.