By all means, PAINT THE INTERIOR FIRST!!!!
I painted the exterior of my Superbee first, and then sprayed the inside like a total dummy without blocking out the windows, and wound up getting black overspray all over the yellow outside!
I could have cried!
Luckily, I had used enamel outside but acrylic inside, so I was able to remove the acrylic outside fairly easily with some light polishing, If you look really close with an Optivisor however, you can still find tiny micro-spots!