Here is the company that I was thinking of using when/if I ever rebuild the Metro's engine:
Tech Line Coatings | Automotive ( Hi-Performance ) Coatings
CBC2 POWERKOTE can be used on the piston tops and combustion chamber as well as the bottoms of the valves.
DFL-1 POWERKOTE can be used on piston skirts and bearing surfaces though hopefully nothing ever touches there...
PKSX POWERCOAT can be used on cylinder walls.