The 17" RFT on my E90 are worn out and I was thinking of replacing the RFT with non-RFT, but I've found a nice set of 18" with a good set of RFT on them for about what the new set of non-RFT tires alone will cost.
The 18's sure look nice-- looks too much like a girl's car with the stock 17's-- but I hate the ride with RFT. I'm sure the 18's will be even worse than what I have now.