So last weekend I decided to finally paint the front and rear bumper trim on the truck. It wasn't until the paint dried that I realized it was dark brown and not dark gray (now I know what color dark walnut is). Well i'm not happy with the dark brown color and I'm just going with black paint this time. I'm going to re spray the bumpers this weekend and I'm wondering if I should try to sand off as much of the existing paint as possible, or if i can just spray over it since it's in good shape. Any advice would be appreciated. Thanks.