http://www.polydyn.com/ did my pistons and exhaust manifold. I haven't tried them yet but they look good.

I thought their prices were reasonable when I had it done and they were good to deal with. The exhaust manifolds were done in a flat black coating. A friend bought one of the coated sprint manifolds for his race car and said he could definitely tell a difference in heat reduction in the engine compartment.
The pistons are pretty with gold tops and black moly sides. I didn't have the grooves coated. Just trying to figure out a head mod where people can see them once they're installed.
My plan is to send a head and get the combustion chambers coated and a modified intake coated. I emailed the guys at Polydyn about the most bang for the buck and their response was that I would really be surprised how much coating the crank would help. It has been awhile since I dealt with them but I think they were referring to windage and not reduction in friction between it and the bearings. I had a windage tray installed in my first car, a Dodge w/318, and it was a noticable difference. The magazines of the day claimed something like 10-15 hp. Neat thing about it was a small increase in MPG and boy did I need it what with gas costing $.50/gal. in the seventies.
Harold