I am new to this but I would like to diagnose my own problems with my VW. Is the only difference between the VAG and OBDII the software. If that is the case, then can you buy a cable to connect your Laptop to your car and get the shareware version of VAGCOM. I see people with directions on how to build the interface. Can you only buy the cable from the VAGCOM dealer or can you use the OBDII cable with the VAGCOM software? So far it seems like build one or buy one for $220.