Okay so I had the mopar exhaust and cai installed and my mpg went from 12.1 to about 11.5. Now theres been people saying that their mpg went up and some said that it went down.....My thought is - if the mods increase your hp/tq wouldnt your gas mpg actually go down instead of up?? I know in my supra going exhaust and intake will give you big hp numbers but will eat up your mpg quite a bit.

I have the DUBair CAI and installed a jet chip at the same time. I saw a 1-1.5mpg improvement. I don't know about HP. Also, the tendency will be to drive more aggressively to test the waters after the install which could easily go through more gas.

I read the same thing, MPG up... Not me... I think a big reason is you're on the pedal a little more to hear the roar of the exhaust :)