How much is the iDrive fault to fix?
Can't say I would be thrilled at the prospect of buying a broken car, it sounds like you'd never get it fixed to be honest as I've been in a similar position before of having a car with a (albeit a much smaller issue) problem and never ending up sorting it out.
It's pretty cheap to buy a second-hand CCC unit and get it coded to your car (like £300); there's loads of them on eBay or BMW forums from scrapped cars/people who have upgraded to CIC.
I had mine replaced under warranty and they said it was around £1k of work.
Received my high kick spoiler from Taiwan on Friday and fitted it over the weekend. It came fully painted with everything needed to fit it, delivered from Taiwan in 5 working days and cost me the grand total of £90!
This is a replacement for my M3 lip spoiler and is the second painted Taiwanese spoiler I've purchased and you really can't go wrong with either the quality of the spoiler or the paint job.
It was an absolute ball ache to remove the 3M tape from the existing spoiler, but it was well worth it. Excuse the early morning dew-covered car but it's been raining all weekend and this was the first chance I've had to take a photo: