I've played Asseto Corsa and Project Cars with Oculus' DK2 (1080p) and it's not nice; everything except the cockpit, and the cars right in front of you, is a blurry mess. I hear Sony's headset is a bit better @1080p, it looks sharper. Still not sure if its going to be enough for a realistic looking racing game.
You're kinda right. The resolution is low across a large FOV, and you really need/want that resolution for the kind of focus areas that you see in driving games quite often (i.e. into the distance at the next turn and apex).
The distance at which you can visually and reliably resolve the direction and angle of a corner is cut from hundreds of meters down to dozens of meters.
On the other hand, after a lap or two, it's not that big a deal - my monitor and VR racing times are very similar (within tens or hundreds of ms after dozens of laps).
And I do absolutely prefer VR racing even with low resolution to monitor racing with high resolution. It's just so much more incredibly immersive, more fun, and provides a better feeling of the car and the track.
It'll only get better... and when it crosses your threshold of acceptability, you'll find it hard to go back as well.