On the advice of my Dealer and a friend who owns a R56 Cooper 'S' and the state of some roads in the area, I did NOT specify Sports Suspension on my June 07 build MCS because I have 17" wheels and Run-Flats.
I find the ride OK but did notice some rear roll, but this stopped once the car was run-in. I presume this was because the suspension had bedded-in.