The FRPP headers fit the best IMHO out of all the ones I've installed. As far as the mid pipe goes they all make about the same power, so it just depends on which one you like. Although a set of gears will give you alot more seat of the pants feel then the exhaust, and it shouldn't change your gas mileage if you drive in a sane manor. I went from 3.55 to 3.90 in my Mach (one of the few automatic Machs) and it didn't change my gas mileage at all, but it feels alot faster around town.