I received my FA HK Binary Firing System package today. I'll be installing it ASAP.
EDIT: I've installed the BFS into a Malaysian 0-1-25 polymer lower, and it fit perfectly. So far, I've installed that lower and pack into my HK94 and a BW5 SBR--in both, that pack fit perfectly and went through all the function checks perfectly. Only thing left is to load up some mags and hit the range . . .
N.B.: I have no problems at all with the aesthetics of the Franklin-supplied safety lever. I must admit that it probably looks better on a polymer pack than on a metal one; however, that's just my $.02.