Silly question, but is the size of the E36/E46/E39 so far off that you couldn't use one of those in an E92? My wife has the Schroth in her E36 M3, and I don't see why that harness couldn't be used in an E92.
Current: '13 E92 M3 Euro Delivery
Wife's: E36 M3
Gone: E86 M Coupe; E30 M3, E39 M5