This is what confuses the hell out of me. I'm looking for heads and I can never seem to find a consensus of where and what to buy without whomever I think I want to buy from getting bad reviews.
Haven't heard 1 bad review about them when you buy them from IMM engines (IMM may only have RHS, not sure) or MRL. If your wanting a new set I don't think you'd go wrong with either of those guys. I have heard mostly positive things about Clearwater, but a few haven't been happy with them like L4Staero