I bet that is a fun car to drive! I'm sure that the wifie is happy.
The chrome side vents were stock on the M edition z3 convertable and coupe. With that being said you probably can buy them somewhere. But then you would be a poser.
I was looking at getting a M edition z3 coupe at one time. The 2002-03(maybe 01 too) had 315 hp stock.

All that hp and so little weight would have equaled ticket in no time. Would have been fun though. Glad I got the 620 instead.