3 spoke Steering wheel
"sport suspension" which really only means slightly upgraded Swaybars, I think the ride's slightly lower also, but still shouldn't make much difference.
Sport wheels (different depending on the year, mine are 17" style 5's)
Black "Shadowline" window trim (instead of chrome) and black trim on doors and bumper
//M badges on the steering wheel and shifter (if manual) and... that's it.