SCT makes really good stuff like tom said. I have the xcalibrator2 which is the same as the 3 except you can have 3 custom settings for the xcal3 and xcal2 only holds 2. greatest investment you can get. 2 step drag launch rev limiter(when you're sitting still you can set the rev limit at say 3500rmp so you can hold the gas to the floor and pop the clutch and take off without spinning tires so much getting a better launch, and its fully adjustable i think anywhere from 2500rpm to 4500rpm) you can advance and retard the timing a little with it tweak how rich or lean the car runs decide at what temp you want the cooling fans to kick on(which is great if you have a car that likes to run hot) and on the drag files the alternator is automatically cut off at wide open throttle giving you that much more power because that is one less thing pulling power off the motor. there are lots of other cool features as well as gas saving that utelitize premium gas to get the best gas mileage and data logging which is a little more expensive because you have to buy the software but its a great program. i think every focus owner whether they are a tuner or not should own one.