Hey all I've posted on here before a long time ago regarding my friend's '94 GT. Well long story short the car is basically mine now, my friend moved out of the country and left it here with me I am stuck between buying it from him for cheap (he owes me :lipsrsealed or selling it and getting a portion of the money. In the meantime I've been spending a lot of time driving it and tuning up minor things here and there; plug change, cap & rotor, new O2 sensors, smog pump delete... My main question, my friend bought one of those SCT 4-bank eliminator chips which I helped him install. I've been doing research on them and it seems like the general consensus is they don't do anything besides firm up the shifts (his is auto) and improve throttle response a bit, with a barely noticeable increase in WOT power. He got three 91-octane tunes (street, perf., race) which doesn't really make sense to me in the first place; these stock 5.0's have like 9:1 compression how can you tune it to run "better" on 91 as opposed to regular (85 around here at high altitude)? I have actually experienced pinging when I put 87 (midgrade) in there running on the street tune which surprised me. So here's the thing, I took the chip out today to see the difference in how it runs and it feels basically the same except the transmission shifts WAYYY earlier (accelerating slowly at part-throttle) and quite a bit slower even when I shift manually with the pedal to the floor (with the chip it hits like a hammer driving this way :headbang. Now I'm thinking, if I instead now bump up the base timing for a little extra oomph and keep the chip out should I get better gas mileage than with the chip? The car has CAI, BBK long tubes, off-road midpipe, 75mm TB (impulse buy courtesy of my friend I know it does nothing at this level) and 3.73 gears. Currently I have been averaging 15-17 MPG with mostly city driving. On another note what's the best way to correct the speedometer with the shorter gears? Do I get a different speedo gear or is it just done through the computer?