I can confirm for a fact that the N42 has both vanos as well as VVT.
Vanos is for cam angle, VVT is for valve lift.
I have never heard of a Vanos going on an N42, but have heard of oodles of Valvetronic problems
I would, before you get to all of this, just change out the intake cam sensor which is two minutes to do, re-calibrate the VVT motor.
Are you electrically inclinded at all.
If you take a look under the plastic cover that goes over the head, you will see a bit fat motor looking like silver thingy (its a technical term)
That is your VVT motor, if you measure resistance between each connector and the body, If you find a resistance value between the coil and the body of the VVT motor, you need to replace it.