Yes, the PS+ version was IMO a bit of a mess. The game itself is now very good if all you want is a arcade racer that looks very nice. easily one of the best looking games this gen so far, and the devs just keep on adding more and more content, but the PS+ version was a bit poorly handled.
Game is worth the asking price though. It also goes on PSN sale very regular as well.
Ah I see, from what I've played it seems pretty fun so far and at £11 to upgrade to full, I'll probably just do it.
The original point was for it to serve as an extended demo of sorts for PS+ members when the full game launched, with the option to then pay a discounted price to unlock the rest of the content. Instead it was delayed for so long that they may as well have just released it as an actual demo to everyone, instead of putting it on PS+ for a month or two long after the full game was out.
The launch was a total shambles, but the game itself is pretty good now and they keep supporting it with new content and features.