Tom,
I have my 53 ready for paint. I talked with several painters and body shops and the consensus was that urethane was the paint of choice. Mine will be single stage, 4 coats of burgundy maroon. The final coat will be color sanded and buffed to a high gloss finish. Material cost for 4 gallons is looking to be about $700, when I add in the sealer, gray poly for the interior, the thistle gray for the grill bars, anvil gray for the bumpers and the black, I will be around $1000 in materials from a local supplier.
My $.02.
Mike