Never ran those pads, but contemplating making brake ducts, since mine finally flew off somewhere in Ohio or Indiana recently. Turner sells the high temp flex duct, and there is a thread on E90post which could serve as a starting point
http://www.e90post.com/forums/showth...ht=brake+ducts
Found a Z4M specific post:
http://www.zpost.com/forums/showpost...40&postcount=8