Using an SC as base car I don't think the RS 2,7 look will be the most natural choice. After all your fenders and bumpers are of the later style and adding a ducktail plus side scripts to a later style car seem (to me at least) like a lazy solution. Either you do it properly with genuine RS looks or you don't do it at all.
Ruf CTR looks? Well at least it was made for the later body style. If one likes it or not is a matter of taste. In theory the Ruf bumpers should make your car more aerodynamic thus lowering wind noise and enhancing top speed.
Personally I like the CTR look a lot. Especially the Carrera rear wing with Turbo housing.
