I've got the Ofna CNC machined servo horn on my cars, and I've been very happy with them. They look great, black with the silver edges, plus they are double fixed, a screw in the top and a pinch screw in the side.
Very well priced too. There's a single and a double arm.
http://www.amain.com/OFNA-CNC-Machin...ox-ACE/p197372