If it is to be paint, I'd suggest a single stage acrylic/polyurethane automotive paint like
BASF R-M UNO HD. Since it's an automotive paint, it's blendable unlike Imron, yet still has the strength and durability of being an acrylic/polyurethane like Imron.
I painted my former Minx in this paint more than ten years ago. I've seen it recently and it still looks new. A quart w/catalyst and reducer is probably in the $350-$400 range...maybe a bit more.