Black Plastic Treatment...

I've tried many of the conditioners and treatments for reviving and protecting the black plastic parts on my vehicles and have had very poor results. The problems are: There are various types of black plastic utilized on different vehicles as well as on the same vehicle...ex., I have had good results with Meguiar's Ultimate Black on
the mirrors of my Tundra but not the mirrors on my Jeep....It spots terribly on the Jeep bumpers, mirrors and door handles but does well on the fender flares. It also puts an "oil" run down the side of the truck after a rain or wash. Anyway, has anyone found one product that produces a decent coverage on all or almost all of the black plastic parts?

I hope you get your answer because I have some of the same problems. Don't know if anything will undo the Sun damage that some of our areas get.