I recently upgraded a 2010 Clubman S to a 2012 JCW Clubman. My 2010 had 16" Bridgestone Protenza tires (non run flats) and I just installed 18" Micheline Super Sports on the 2012 JCW (did not enjoy the 17" Conti run flats that were on the car). The problem I am experiencing is a little hard to define but I will start of by saying the 2010 S was superior in handling. The steering was noticeably firmer and tracked so well that I had amazing confidence at speed with that car. My 2012 JCW is looser even in Sport mode and the overall car seems less controllable at speed. I feel what seems like more sway in the body and the car does not track like my 2010. I had the alignment checked and it's nearly perfect. The JCW has the factory sport suspension and my 2010 s had stock suspension. For the extra cost of the car and it's upgrades, I would have hoped for better or at least equivalent handling but it's not.
Any feedback will be greatly appreciated