The SCT XCal 2 will datalog all the parameters the same parameters a professional tuner does when tuning a car - but you'd also need a wideband to do it right. The Xcal 2 will also read and clear DTCs and you can make small tuning changes with it either with a free program called Exterme Tune or if someone gets it from a dealer like us who has SCT's latest software, changes can be made right from the unit itself without a laptop. The base files - up to three, are put there by the dealer and if you need changes made to it - the dealer can just email you a new file.
For an additional $300 you can get the Pro Racer package to add to it so you can have all the software us dealers use.