Hello. I have recently stripped down a old GT outpost Trail that i have had for many years, After trying to figure out what i can do with it i have decide just to paint the frame and put some nice slick tires on. I have found Sheldon Browns website and that has helped a lot but i still have a few questions...

First, This frame is powdercoated, It has quite a few chips in the paint. So ive decided to make it Flat Black. Can i just prep and paint this thing like i would a car?

Secondly, Bottom Brackets. The one i took out is a 116, Should i try and stick to that number or can i go +- a few or does it depend on the crank??? No idea if this is a dumb question sorry, Im new to this lol