I was a bit fed up with the faded grey plastic bumpers on my 9 seater MK7. Tried all sorts of various back to black products and before I go down the bumper paint, or heat gun route I thought I'd give Owatrol Polytrol a go after seeing some good reviews of it. I cleaned the bumpers then painted it on with a paint brush, and then wiped the bumpers over with a clean cloth a few minutes later - simples! The finish is really good and the bumpers look like new again! A week later and they still look exactly the same so I'm quite hopeful the finish will last a while.
https://www.owatroldirect.co.uk/product/polytrol/