Willenhall - as in around the Wolverhampton area in the UK?
You've listed a Z4 cabrio as the car you have, what year is it?! I have an E39, and I know there's a oem hybrid analogue/digital module for those cars. So I'd assume there's one similar for the Z4, but I'm not 100% sure. The E39/E46/E38 and E53 all share the same setup so can use the hybrid unit, however they do cost between £425-600 on german ebay whenever they appear - so second hand and with no guarantee, seems very pricey to me. Hopefully, as the Z4 is much newer there's an easier and cheaper solution.
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