She doesn't look under the hood, so the Jet unit wouldn't be a big deal. There's nothing to the installation or removal of those, it seems. The Hypertech product seems to be much more customizable, with an installation similar to reading the trouble codes. Is there any evidence that the software has been flashed with a unit like Hypertech, even if it has been returned to the factory program? I'm paranoid about warranty questions.

what would be the best way to calculate ur mpg. I attempted to do some simple math simply by driving through a quarter tank and multiplying those miles by 4 then dividing the size of the fuel tank (19.5). Im hoping I'm did something wrong because my outcome was like 11.8 mpg. i don't have a lift and haven't done any real mods aside from a little weight like the sliders and the rack. just got the oil changed, my air filter i clean pretty periodically, tire pressures are good, and I'm not much of a heavy footer... any ideas?