I have the 19" 296's, they haven't cracked yet and I put non-RFT's on a couple of months ago. The ride improved a zillion percent (Conti Sport 3's) the other issue with the 19's is the scarcity and price of decent rubber to put on them. The handling, I don't know as I have never had a bMW with 18's, all my others have been 19's with one exception , a set of 17's on an '03 Z4.