Please be careful using silicone oil near things you want to paint later on: everywhere there is a trace of the silicone oil, even years later, you will get "fish eyes" in the new paint. This is the reason I've banned it from my house, the overspray will get on literally everything and it's difficult to prevent and remove.
Silicone will make plastic on the outside of your car appear like new again but the effect is short-lived, like two weeks, and there'll be a period after that where it looks blotchy. Door rubbers are OK with silicone but I've used vaseline to similar effect.