If it's ICV issues, I can't think of any damage that can be caused by driving it for 2 more weeks. In my past experience with ICV issues (not with M3), once the first symptoms shows, you have about 2 weeks to get it fixed before this happens:
At one point, the car will be undrivable. Every time the car goes into idle even after a peroid of normal driving, the idle will drop so low to a point where the car will stall. In this case to keep the engine running, you need to constantly have your foot on the gas pedal, needless to say, then this becomes a safety issue and you'll need to get the car towed to the dealer.
1. Bump up the appointment
2. don't drive your car unless necessary to delay the timeline (not guanteed it'll continue to work in 2 weeks)
3. anytime within the 2 weeks, drop your car off at the dealer, and use a rental car (not ideal, your car will be sitting in the dealer service lot with minimum supervision, unless you can get them to store it inside for 2 weeks)
Last edited by mdosu; 11-14-2012 at 03:51 PM.