Hi Steve in sunny Australia not sure if the 2Fifty cal has got a different shape Window frame, but a friend of my who has the Z3 fitted chrome one over the original window surrounds. He used BMW chrome parts which he stuck on with 3M double sided tape. He got a friend of his who is a windscreen fitter as he had to pull back, the rubber to fit. part numbers covering aperture left-hand 51168398505 right-hand 51168398506, he said, the parts are about £46.62 each and also you need 4 clips could not remember the part number or the price, and could only be fitted to 98+ cars, not sure if this helps, anyway, good luck John James