I have an SVT and am averaging close to 27 MPG's since I've purchased it brand new. I drive normal, a few quick starts per tank, but usually taking off normally and shifting at 3k.
The lowest I've seen was low-mid 23 MPG's, but that's when I have a really heavy foot. The highest I've seen was mid 31 MPG's.
I have an intake and throttle body for mods, but it really hasn't had any effect on my MPG's. I have a tune, but I'm still on the first tank. I might have picked up a MPG, but it's too early to tell on one tank.
Give the toughest job to the laziest man and he'll find the easiest way to get it done.