I just got done pulling my Jet Chip. As far as I can tell the car still runs the same. I wasted $295 dollars on this thing. I am about to go see if I can sell to some sucker...err... person on E-bay. Take it from me...don't buy pre=programed chips!
best to get it after you have a midpipe (so the chip can turn off rear 02 sensors), after gear change (for speedo calibration), and intake mods (so it can adjust properly for Air/Fuel Ratio).. get it tuned for high octane as well (chip adjusts timing).