I've used this dye product for a while because it lasts a long time. It's a tedious job to tape off everything, but in the end the results are tangible.
It may be hard to see, but the flip cover is not yet dyed in this image:
I did all the front black trim using a foam lollipop. I trimmed the foam lollipop to be tapered so I could get between the holes.
Once you tape off, the work goes quickly. I also did the black strips under the doors (not seen here).
I tried it on the easily faded black trim at the back of the engine bay. I did one side and ran about 5 months with no change, so I did the other side. Not perfect, but looks much better.
For comparison, here's a close up of that black trim pc at the back of the engine bay. You can see where I taped off the sticker and left some faded area behind...notably just under the sticker.
