Your dealer won't, but nearly any tire place will. We used America's Tire (Discount Tire outside of CA) to change the Bridgestone RFT's to Michelin non RFT's on my wife's previous 135i. They asked if I understood I was not putting RFT's on and that was it.
Many folks do switch to a higher spring rate after replacing RFT's, but I'd try it with just new tires before deciding what to do. Plus there aren't many spring options for the E84 yet.