they have them in the 3 series ragtops, I wonder why they didn't use them on the Z4?
Yep and they look really smart, don' know why they didn't use them on the Z4

I never thought of that, the silver seems to break it up quite nicely now that you mention it.
Try and pop into a couple of dealers, the piano black will also mark really easily, fingerprints etc. Have a look but I would say silver would be a better bet (it's like a brushed aluminium finish).