BMW E30 Wiring Harnesses | Wiring Specialties Plug and play aftermarket wiring harnesses for Nissan, BMW, Datsun, Mazda and Chevrolet's with LS1 and JDM engine swaps. Startup guaranteed. Made in USA. M30 in an E30, what wiring harness? • MyE28 Apr 22, 2006With any of the e30 harness you will have to cut the sheaving here and there to gain a few inches of wire, like running between the alternator and starter, or up the the fuel injectors, but all the m30 specific sensors will plug right into the e30 harness. if you have any other questions feel free to ask.