I think u should strongly consider the sport line as a substitute to the m-sport, as u will get sports seat, sport and heated steering wheel. The only trade off is lack of sport suspension. IMO the "normal" suspension is no slouch vs. the m, I did drive both and the difference in steering feel and suspension stiffness was minimal. Perhaps I didn't drive it hard enough as I had my family with me. It's not as if we are comparing the suspension of a minivan to an M car.
Also, as ur getting black exterior regardless of trim, the exterior visual difference is minimalized as the black plastic trim (instead of painted trim on m sport) would blend in better on black compared to a light colored car.