I had ordered 17's on my '07, R56, MC
-S. When the original tires were due for repacement, around 20K miles, I started shopping around. I was suprised to find that for the price of the RFTs, I could buy two sets of non-RFTs. To make a long story shorter, I located and bought a nice set of 16" tires and wheels on ebay with about 1200 miles on them. They were RFTs. I ran them for a year, sold them on ebay, made about $100 profit and bought a new set of 18" RFTs Komhos for the original wheels. I do know that there's no room to store a spare on the MC
-S; so if you go with non-RFTs, you'll need to carry a can of "fix-a-flat" and invest in a small plug in compressor to carry around.