My experience/opinion on the Performance Controller.
With the Performance Controller, my Passat now drives like an Audi with a Torsen differential, there is no longer any hang-on all-wheel drive.
As I regularly drive company Audis with Torsen differentials, I can assess/compare this very well.
In the curves, the handling is now 100% neutral, or when you accelerate in the curve, it even oversteers slightly, so that I have had to correct the steering 1-2 times, which is unusual.
The way my Passat drives now is how it should have come from the factory.
The Performance Controller was the best investment after the ProBoost treatment in terms of handling.
Review from a satisfied costumer. 
