^ i'm not quite understanding your question. that sounds like what i did...?
i painted the "valence" part because it lines up with the wheel well. the actual "flap" part rests on the inside edge of the wheel well, so if you painted any part of the flap it wouldn't flow correctly. there would've been a hunk of red in the wheel well, not lining up with anything. valence is body color, flap stays black.
i didn't leave the flaps because they look dumb IMO, so i trimmed them down really thin.
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