for every day use i'd go for the MR, but for more "spirited" driving, i'd go for the RS.
MR & RS have about the same power but the RS is lighter and therefore is a faster accelerating machine (as mentinoed earlier), but there are few cars which can even think about taking on a MR, Even fewer can take on an RS (specially on a track)
Remember that neither I not PW condone "racing"