I want to paint some dark grey plastic (specifically the kind found in a car interior), and i hear Krylon Fusion is the product to use. however, i am just curious, would primer be recommended before i use the Krylon? would it hurt to use primer? Because im reading how this paint soaks into the plastic rather than sitting 'on top' of the plastic, and so priming may prevent the paint from soaking in as well. i've also hear people using krylon fusion AS primer, if thats the case i don't think primer would be necessary. any advice?