Yeah, AFAIK, no knock off cables exist that work with CAN-BUS, and the knock off cables don't do everything. I had one for a while, and it worked for simple mods, but once you start getting into logging, recoding for navigation and stuff like that, you need the real deal. Although it is expensive, look at it as an investment. It's a great tool to have, moreso if you do a lot of your own upkeep on the car. I've had mine for years, and its paid for itself.
We have the Hex-USB-CAN on our website for $356.35 (with free shipping) if you're interested (http://www.europaparts.com/vag-com-d...ross-tech.html
), and then you just download the software (you want release 908) from Ross-Tech's website (http://www.ross-tech.com/vcds/download/