Here is a very good product for tires that I have also used on all the plastic including the rear facia. It is water based. https://www.amazon.com/Dressing-Prot...%2C164&sr=8-31
Follow is with this: https://www.amazon.com/Waterless-Was...s%2C160&sr=8-3
I don't particularly like the petroleum based products. 303 is a good product line also. I use this brand to clean and waterproof my convertible top.
Sly - everything but Onstar.
Mods - Clearbra 3M tape, splash guards, PCMforless.com custom dyno tune.