M Aerodynamic Bodystyling: Specific front and rear bumpers and side sills. Alloy Wheels: Standard 20-inch Star-spoke style 740 M wheels, often upgraded to 21-inch or 22-inch designs. High-Gloss Shadowline: Blacked-out exterior trim, including roof rails and window surrounds. M Sport Brakes: Usually finished with blue (or optional red) calipers.