I have zenki front and rear bumpers and they are starting to get dull. Right now they are looking like a faded gray color. Im wondering if anyone has painted they're bumpers, is it a good idea or should i just leave them alone? Im about to paint them black with a clear coat. Any pics of painted zenki or kouki bumpers would be great.

According to me, you can use powder coating instead of paint. That will be better option as it is thicker than paint. PVC wood grain coating can be use for aluminium or other metals.