Yes, I have G Sync enabled and rF2 limited to 240 FPS in the player.json. Normally I have a stable 200 FPS in normal conditions on a new circuit with the updated PBRs, with this app it drops to around 180. On older circuits I can keep 240 with no problems. I haven't tested in the rain, but it doesn't worry me because obviously I already know that I'm going to lose performance and there aren't that many races that I normally run in the rain.
It's not that I have stuttering or tearing problems, Gsync solves that for me, it's just that the feeling of going above 200 FPS is much better, everything runs smoother and my eyes don't get too tired.
Interesting, I feel the lack of smoothness when i compare 60 fps to 120/144fps, but I don't have the equipment to reach the 200 fps and feel the difference.