Hi chap, have a look on RealOEM.com, not the best website to use but if you look here:
http://www.realoem.com/bmw/enUS/showparts?id=DU93-USA-11-2006-E86-BMW-Z4_M32&diagId=51_5960
it should get you where you need to be. That's for a Coupe but I think the parts are the same for both E85/6M.
It says $450, so double it and you'll be in the ballpark. I think you'll need it painted on top of that price. It can be easier to wait for your colour on eBlag...
Stevo