I checked my options on a vin decoder and it said my car has an “M Sport Suspension”.
As I understand it, my car has the "Sport Package", which included the suspension noted above that is among other things, lower than a car without it. I think that the brakes were also a bit bigger than otherwise and the car was equipped with the Sport button to modify steering and throttle response (and shift points on automatic transmission cars). Automatic transmission cars also got paddle shifters too. And you got the 18 inch Style 108 rim.
More info here:
http://www.bmwz4roadster.net/brochure/2007_E85-E86.pdf