Most of the systems will all do just about the same thing, alot of the differences are in the tuning and software. The FAST system uses a true wide-band O2 sensor that is accurate over a much broader range. You have the option of running in real closed loop mode, not just to tune but all the time. The data logging is a big plus also, with the new windows software it allows unlimited data logging. You plug in your laptop start logging and just drive for a while, stop and replay looking at all sensors, ignition settings,injector pulse width, everything you need. If something needs changing then click, click, enter and your done. It's really not that difficult you just make small changes and don't get to aggressive.

John