Free Car audio what should i get?

Pioneer or Kenwood, all day long. Based on my experience and research, the other brands are not worth your while and do not have the research or design work invested like Pioneer and Kenwood have.

Clarion can be hit or miss. I'm not sure what products they are providing with each brand, but I would advise tri-axial 6"x9" speakers in the rear and coaxial 5-1/4" speakers for the front (probably on the kick panels). Pioneer head units typically have a lot of options, while Kenwoods are more user-friendly. I've had good experience with both. My best experience has been with Pioneer speakers (out of the list you provided).

Good luck, and congrats on the prize!

-Mike