Googlet e28 polizei og fant dette, http://www.mye28.com/viewtopic.php?t=70942
They are called "Aluett", and they later became what now is branded "Rondell", this model is no longer available, now the Rondell 58 is the one available, but its more made for modern cars and less agressive. This one has more sharp edges and deeper lip. dimensions is 8,5 and 10" wide, 17" diameter.
Its poweder coated BMW Alpine White and then wet-painted centre to black.