Wanted 108 Rear Rim - I have taken mine in for refurbishment and One of the rims has 2 cracks in it! Whilst these can be welded I would prefer to replace it.
There is one on Ebay at the mo.
http://www.ebay.co.uk/itm/Bmw-Z4-2008-Rear-Alloy-Split-Rim-BBS-/150836186613?pt=UK_CarParts_Acc_Wheels_tyres_Trims_Car_Rims_ET&hash=item231e898df5
Thanks FMA, I appreciate your efforts, as I had the reburbishing companies spare whhels on my car I had to make a decision, so as I was not able to find one quickly, I have gone down the welding repair route, so the finnished items are now back on the car ( as from yesterday). Inital reaction is I am pleased to have replace the run flats.