Here's my thread on the matter.
http://x3.xbimmers.com/forums/showthread.php?t=663008 I'm not a RFT fan. Conceptually, it sounds good. But if you get a couple flats in a row and have to pay for a couple new tires (about $350 each)... when normally, you could repair them yourself or have it done for about $10... The option becomes very expensive.
Also, here in the US... the tire that come on the X3 M-Sport (GY Eagle LS2, 19") are impossible to find except through the dealer (with a couple day wait time).
I think if the tires were commonly available and cheaper it probably wouldn't have been such a hassle.