hmm... So that tells me the rear beam is same on both the cars..
Could be, could also be that just the bolt pattern where the brakes bolt to the axle are the same. the Passat is prob going to be wider that a jetta, GTI, Golf or Corrado?
The passat rear axle will be wider. Should be similar to the Jetta III rear axle. It will most likely have a torsion sway bar built in to the beam.
Any 4 lug rear disc brake set up will bolt in to your car.