Just to add...
I just got my car back and had over $1000 done on it something with the vanos. I reported the problem twice while under warranty and they attempted to fix it but nothing worked. Same problem happened again this past week and they "found more error codes" and changed some parts. My car is now 15000 km out of warranty and they fixed it for FREE. So like damameke said, did you report it while under warranty, cause there is a good chance they can do it for free...just gotta press them a bit.