any paint will apply well to the vents & door handles, just scuff it down with 320 grit paper and it will look fine after its painted. on some plastics, the texture isn't very good, and the paint won't stick in certain spots. I've painted everything you have mentioned on my previous cars, but have yet to mess with 93 integra.
if you decide to paint the dash..make sure you get vinyl paint, the good stuff is like $20 a can.
good luck with the painting.