Interior

I checked everywhere i couldnt find anything.... Do i need to prep the interior peices beofre painting? Do i use primer?

Well the best awnser is yes, but not all peice need to be primered.

Unless you have a black part that you want white or yellow or any light color, you don't need to prime before. But lot of modeller do prime all part, it give a better finish, but not a must for everyone.