This was just installed yesterday so I do not have info on mileage. I have much better response on the low end. Took a short trip on highway and I got up to 75 mph pretty quick. I have 6 speed manual, on the highway, as soon as I hit an incline I have to downshift to 5th gear. I am hoping this corrected that problem, I don't have an answer yet. Dont really care how fast I go, but don't like slowing down on inclines.
jet stage 2 real easy to install. have to use 91 octane or better, but with all the rewards cards out there I get at least $.10 a gallon off so I don't feel too bad about it.
Also the thermostat needed to be swapped for 180 degree stat. 1 bolt on housing was real hard to get to, throttle body was in the way.