I think this topic has come up in the past ,what can you use to paint the plastic inner fenders?I used "Krylon Fusion" that comes in large spray cans and needed about 4 cans to do the job complete. It's designed for plastic lawn furniture. Remove the inner fenders, sand any rough spots first then wipe them down with lacquer thinners.I found it a little different than regular paint, you need to spray mulitiple tack coats before you can spray the final wet coat. The final finish comes out very smooth with a nice semi-gloss shine.

You can use pretty much any Automotive finish on the market. You have to add a flex additive, prep is the fundamental first step to a good lasting finish but it's no harder than painting metal or fiber glass.

I think most of the new cars now days are about 20 to 40% plastic anyway. someone makes a three stage spray paint, in cans, you can get in the auto store that has a flip/flop type effect to it. Maybe that is Duplicolor. I always wondered what that paint looked like completed and dry. Not curious to go spend the money to buy it though, don't need it for anything right now.