Plastic primer or automotive primer?

I just got some supplies for doing my first case paint job, it's a crappy case but I wasn't going to try out my noobish skills on my Chieftec Anyway, it's an old gateway case I got for free which is of course a plastic/steel case. So my question is, do I use automotive primer or the plastic primer?

Thanks

I've used regular primer with success on case plastics, but it would probably work even better with the plastic primer because of how well it holds onto the plastic.

My main concern was that since, the auto primer is designed for wetsending, I was wondering how the plastic primer would sand :/

In my experience, any paint is sandable. Even the rubber based black bumper paint. You just have to give it longer to dry all the way.
Plenty of water, and light pressure.

The "sandable" on the can means for dry sanding while shaping bodywork and getting rid of grit marks from heavy grit sanding. It gives you a visual of where the low spots are.
Any paint is wet sandable.

If you have any electronics on your bezel like USB ports, make sure to detach it while wet sanding.