You haven't got your car yet Kev!
I'm not sure. I keep it in medium for myself, but switch to comfort if I have passengers. (Especially mother, coming up 93!) I only tried the sport once, the day I got the car. I don't really want to start thrashing it till it's done a few more miles (mind you, we're about 1,000 now).
I probably need to experiment a bit more. I probably wouldn't have got it if it wasn't for the aged parent, but then I'm the one with the cloth seats and the 17s and the 310 audio system.
Rolfe.