Diagnosis System: Buying Guide & Recommendations

Hello everyone.
I hope you can help me and give me some advice on making a purchase.
I would like to buy a diagnostic tool.
Since I'm having trouble understanding all the different connection options (KKl, KKL+CAN, HEXUSB+CAN), I wanted to ask which one is right for me, or rather, for my car.
I'm currently driving an Audi A4 B6 2.5 TDI (engine code AYM).

I would be very grateful for some tips.

Best regards,

Hello,

The Audi A4 B6 (type 8E) uses either CAN or the older K-line communication protocol, depending on the year of production.
You can find a list of which vehicles use what here:
http://shop.dieselschrauber.de/VCDS-Fahrzeugliste.pdf

Since all the new models support CAN, I would recommend the professional system (HEX-USB+CAN).

Best regards, Rainer.