As far as primer. . . some people would say just paint it being it's a stock body. But the problem that could happen is the paint won't stick on well to the body. So I say primer it.
I won't go too much into detail about prepping and painting your body, since there are some good tuts. and build/paint threads here in the forum about it
I would give the body a quick wash in a light detergent bath (get rid of oils and stuff that get on them when taken out of the molds) and let it air dry.
Don't need to mask things i feel. I can't tell from the pictures and don't have experience working with Mini-Z bodies so I can only assume the body doesn't come apart as in front and back bumpers/grill like a xmod does. If it does it helps to take it apart and spray it that way. Key part here when primer so things don't thicken/build up is even long strokes, best to practice on scrap.
But that's just a small bit of advice I can offer. Like I said check out some of the tutorial/build threads. Since Doc Kustom posted his threads are good to check out, especially his build threads
