No offense intended but, who are these guys? DO NOT put Copper-Cote(spray on stuff intended for cast iron Chevy engines)or anything else on any Mercedes-Benz head gasket. But especially anything with copper in it. The difference in electromotive force between copper and aluminum sets up a chemical reaction making the aluminum the "sacrificial annode"....it will pit. This is the same reason Mercedes says not to chrome plate alloy wheels....they have to be coated with copper first in order to make the nickel and chrome stick to the aluminum.
Sorry to but-in....but I am getting a little concerned. First, they figure the head is "probably" warped and they want to cut it without even checking it yet. Then they want to spray "goo" on the gasket...Nah, they probably know what they're doing and I'm just being too picky.