MOTK made me aware that there's an OE block off cover for the wheel arches (From the 3.0 Z4) you can buy for cheap. However I will still include the block off plate if you want it. The OE one in plastic cost around 5-6$ each side.
Part number 5 in this URL:
http://bmwfans.info/parts-catalog/E8...ch_trim_front/
Part numbers are:
51717056403
51717056404