This document details the steps required to converting a sealed beam headlight system as found in the 90 on BMW e30 to an US Ellipsoidal/Euro Smiley/Cibie CSR based system. The US Ellipsoid system uses single element 9005 and 9006 bulbs for the high and low beams respectively, whereas the Euro Smiley and Cibie CSR systems use a single element H1 bulb for BOTH the high and low beams.
E30 Headlight Wiring Instructions