Tried for a season of F1 and one race in F2. It does what it says, it gives you a reverse grid compared to the qualyfing.
The problem is that for some reason, also made all drivers several seconds slower. On singapore was specially bad, a race that i managed to do laps 7 seconds faster than the Raikonnen in the AlphaRomeo in front.
I was playing on carrer mode, with AI on 90.