IMHO, in the case that BMW does recall the cars to work the rear suspension, I would go back to the stock spring setup for the fix. Anytime, I modify the any of my cars, I keep the stock parts for reasons like this. If you are willing to personalize any vehicle, you must understand that you are opening a can of worms, and you must have the funds to handle any issues that arise.
Just my 2 cents...
///2013 M5 Alpine White/Black,Orange County CA\\\