Did a quick job on the E92 M3. The rear back box has (had) two earth straps to stop some kind of electrical interference which can make the DAB radio signal choppy. Mine were both missing so looked into how much they were (part number 12427840591) - £25...each! £50 for two tiny earth straps! Absolutely mental.
So I went online and found a couple of earth straps on eBay (https://www.ebay.co.uk/itm/9-Classi...ble-Flexible-Tinned-Copper-Braid/121930637020 - ask for 10mm diameter holes) which are identical to those that BMW sell - £2.99 each inc del.
So I went online and found a couple of earth straps on eBay (https://www.ebay.co.uk/itm/9-Classi...ble-Flexible-Tinned-Copper-Braid/121930637020 - ask for 10mm diameter holes) which are identical to those that BMW sell - £2.99 each inc del.