There were 1027 pre-2014 specification cars produced, according to the numbers for the one and only M3W recall, to date. ... A "customer contribution" in the region of £10,000 is now required, plus payment for any other work found during the chassis change. ...
Thats a big potential hit on resale values. If there is say 50% chance you might need £10K of work, then that wipes £5K off the value of your car.
The M3W services fix looks like a complete rebuild so is unlikely to be inexpensive either! Although it looks pretty good!