I used a brush to make the spray, choose a flow rate of 1 or 2. A little blur, noise, rain etc, added some reflections, but they're only just visible, also selected the tarmac, created a new layer and filled it with black, then chose soft filter 80% opacity, and erased some of it to look like a dry line is appearing on track.
Yea don it would be good if you could choose to open the whole track up, so you can use the rally X and main track, would make a good pic