had them before, better throttle response not much better if at all in mpg. they are a PIA to tune right also. too lean, too rich. winters can throw all the settings off that you set up in the summer. can be very picky. will run fine all summer then diesel every time in the winter, have to retune it, got to be a PIA so i sold the truck and started over. wouldnt spend 300 on one again, rather rebuild a stock one for alot less.