AK Xtreme Metal

For best results, yes.

Additionally they do sell a black base coat. Soooo, well there must be a reason. Seems to me in my watching of some reviews of this stuff that the stainless steel and durametal colors liked a black base and passed better as chrome than the chrome did for things like shock struts.

Definitely use a black coat for shiny surfaces like chrome or polished aluminum. I have sprayed other shades directly on a primed surface with good results.