Before your ass gets flamed around here, let me advise you to use the search function. Have a look in the how-to archive or go to ScaleWiki, these types of questions are asked frequently.
You donīt always need a clearcoat to make a car shiny, is the color is SOLID, you can polish it out. But if itīs a metallic paint youīll need a clearcoat to make it shiny (donīt even bother polishing metallics).
Iīd recommend you to buy some spraycans, the results doesīnt even compare to a brush-painted paintjob.
Good luck!