It's an 'Ireland ' thing and Our 'brilliant' roads , I specced My MC with 'Sport' not SS in late 04 and now have specced My R56 with 'std' suspension , I have found the 'optimum' for Ireland to be 16" wheels ' non' runflat Tyres and 'Sport' suspension , I agree the R56 is a different kettle of fish and the new generation of 'runflats' are much more flexible in the sidewall than the 1st generation .also remember the build quality is much improved in R56 and the dash etc won't 'rattle' like R50/53 .It's not long until the 18th anyway BUT if You go for a test drive make sure You drive a route You know well and compare suspension performance with Your current car and both Std and Sport on R56.
Gerard