I have a couple of quick questions. I know that the unit has to be flashed back to stock by the original owner, but that's about all I know. Is it possible to get one that already has my ECU code, or are all of the codes different? And speaking of ECU codes, where can I find mine (06 ZX4)? and finally, does the year of the original owners car matter? Thanks very much in advancefor any help you can give.

With the xcal 2, it would be best if you buy one that already works with your ecu number. Not all of the codes are different. You can find your ecu code by opening your glove box, adn let the box hang down so you can see inside the dash. once you do that, it will be off to the right, and you will see the ecu. the number will be on there...

the year of the previous owners car shouldnt matter, but, when you do get the tuner, you will want someone to make you a tune, specific for your car, so you can tell them what modifications you have, and they can tune for those specifically.