I'm not selling any but I just got a set (includes both parts) brand new from BM Town and cost £85 which included delivery. The quality is good although I did trim off carefully some small areas of over casting which in all fairness was just me being very fussy, this would not have stopped them from being fitted. I've not got around to fitting them yet but will do so tomorrow and post some pics.
Bought some from the good old US of A,and well pleased with the fit and finish.
http://www.z4-forum.com/forum/viewtopic.php?f=2&t=14463&p=222901&hilit=kidney+grilles#p222901
Try modbargains.com for a set. I got mine from them, being in Canada they were sent quickly from the US and well packaged (wrapped then boxed), and fit immaculately. Send me an email daveysew at yahoo.com and I can send you some pics.