https://www.autogeek.net/gtechniq-c4-trim-restorer
Best stuff I have ever used. Yes, it is more expensive initially, but, you don't have to apply it monthly.
Our dad's 2006 Tundra is outside 24/7. The plastic trim was starting to fade, I applied different plastic protectants over the last couple to try and help it from fading further. Tried 303, Optimum Opti-bond, and Optimum Opti-coat tire dressing and protectant, and Blackfire trim and tire protectant. Our dad asked to look for something different, something that would last for more than a month.
All the ones I had tried worked well until it rained. The rain started washing the protectants off. After about a month, the trim looked as if I hadn't applied anything.
Gave this stuff a try. I was hoping it would be good, I was surprised just how good it is. Not only did it restore the color well, the restored look has lasted for over two months now even after multiple rains. It doesn't wash off, and it is standing up the 90 degree heat we have been having.
The key is that the plastic needs to be CLEAN, so, the product can bond properly. If you prep carefully first, I think you would be impressed with the product. I am.