Hi Christian,
The guide uses the same vw/audi lead as Arnie mentions above but it has a 3-pin ISO adapter plugged into the end. Obviously if you have a cross-over car with a 4CM ECU but a 16 pin OBD plug you can do without the ISO adapter.
Later cars complied with the OBD2 protocols, so you can get away with a generic tester for these cars.
The latest version of the Unidiag software is hosted here too - you can download it using the links I put in the guide.
PM me if you are having trouble with getting it connected.
Regards,
Steve