Yes the throttle flaps and whines before you start the engine, and again when you shut it off. It's just checking it's position for safety......always a good thing when you have no mechanical link to it!
Yeah the VVT adjuster is £450 from VW. The phasing mechanism itself rarely fails but the oil control rings you mentioned can indeed fail, and they can also wear deep grooves into the adjuster, but I wouldn't mess with it unless you get "slow response" fault codes. The only reason people HAVE to replace them during a chain refresh is when the crappy little shallow headed bolt rounds out, because drilling it out usually fooks the VVT adjuster.
AKS Tuning sell the oil rings and should be replaced when the chain cover comes off.
