This is the one I have. BMW USB OBD Diagnostic cable INPA Ediabas DIS SSS GT1 | eBay
If you think it's confusing, it is. I'm in IT and i still had trouble getting it all to work. what ever you do, I recommend wiping and reloading the OS on the laptop you choose to use before you start.
Once you get everything working, then you have to figure out how to use it and what everything does. You can't just start messing around because it's too easy to turn modules into useless chunks of crap...