Dealspwn: Project Cars is easily the best multi-platform racing game available, not that the competition is huge. This is the best price we've seen it for on the PS4 too. This is £8 cheaper than the next best deal.
Project Cars likes to sit more on the simulation side of the track, but there are plenty of driving aids to ease newcomers into the experience and it's incredibly satisfying as you slowly adapt and turn more of them off when you tame the wild vehicles. A worthy alternative to the likes of DriveClub and Forza.