I always bet on black...
IMO, the flexible bumper coater is a good choice, it's what I used on the last "go round" with the hood insert. A flexing agent is useful in a piece that experiences not only road/trail vibration, but also, more extreme temp variations (expansion & contraction) than anything else on the vehicle that would be painted, calipers being the obvious exception.
FWIW, I've painted my insert 3-4 times, & the SEM Bumper Coater is the best finish I've achieved to date, only time will tell if it's durable.
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