I do believe you get better gas mileage without them...or maybe it's only with the tail gate up as opposed to down? I can't remember it was on myth busters once.
Really? I don't see too many merkurs around that's for sure, 25 is pretty good. I thought about putting a cai on it and possibly a bigger exhaust, depends what happens next year though. I'm supposed to be modding the stang, not the truck.