I bought my cable off Ebay about 5 years ago, so no idea where to get one. And most of the VAG forums I use are very snobbish and will recommend getting the proper one.

VAG COM is easy to use. Its like you say. Plug cable in, run program, get someone to read the figures that know what they are looking at.

Seatcupra.net has a request area where you can ask if anyone has vag com locally and get them to do it for you.