Yeah that Utopia map is gonna be free, cars you have to pay for.....personally I don't see much point.
My Plus money has done that. I mean it actually depends what the price is. If it's a couple of bucks I will.
More info here: http://blog.us.playstation.com/2015/07/30/rocket-league-supersonic-fury-dlc-pack-coming-this-august/
Some update information here: https://www.reddit.com/r/RocketLeague/comments/3fcnc2/103_rocket_league_patch_megathread_changelog/