looks like only this will fit the E90 M3.
http://www.shopbmwusa.com/ProductDet...&ProductId=895
clean fit, but if you don't mind manually setting it up everytime, they're not the "curtain style" are they? You need to do the suction cups...
I know hindsight is 20-20, but I didn't think I would need shades either, but I have them on my E90 and are quite useful, especially the motorized rear shades. OEM also allows side windows to open with the shades up.