How much mileage decrease could I expect going from a #8 plate to #0 plate with normal driving?

Thanks......

 

From my understanding you shouldn't notice any difference with a light foot. The Gov. arm generally rides on the AFC foot until boost is built, then the arm slides back letting the Gov. arm ride against the plate. If you put in a valet switch you can keep awesome mileage, because the AFC arm never slides back. The only downside is they are pretty slow with it on, lol. I might be way off but I'm pretty sure thats somewhat accurate...