should i primer first
 

This ones for B.C.I have the paint foe my supra now i wanna paint the rims and the hood black should i primer the plastic first.:bdrop:

Primer helps the paint stick- just make sure it's the same brand and type. The paint has to work together.
Some paints don't need it- and it helps a lot more on bigger parts like hoods and bodies where you want it to be smooth.

Annother time you want to use primer is when you are painting something dark a light color. Or, you did a lot of custom work, and you want it to look really smooth.

thanks