I do not have VAG. I have a universal autel. (I would be up for purchasing one though) The RPM needle will move up and down slightly, and you can feel it in the car. It has a leaky engine mount, I just figured thats why it never felt smooth at idle.

As far as vcds. I do not know how to use one, and have only seen it on one website. For like $600.00. That's a bit much. IMO