The key is maintaining an almost constant amount of throttle in 3rd race such that you're barely touching red/fluctuating between yellow and red zone for engine heat. The more stable the throttle the higher average speed u can maintain. My speed range is closer to 334-342km/h for Series 12 and have gotten multiple times of rank S, although might be easier for me as I've been playing not too arcade racing games often
![Tongue Tongue](https://forums.rpcs3.net/images/smilies/tongue.png)
Also changing the "red"(engine tuning) card in [card set up] may help boosting the horsepower to ~943hp highest for my save (though doesn't help average top speed in 3rd race). I might've forgotten checking that before uploading the save.
I'll update this post after testing with your setting. Thx.
EDIT:
Performance worsened with ending screen stuttering like hell. On plus side game no longer freezes after that though sadly I still ended up in an eternal black screen. The whole RPCS3 then crashed when I Alt+F4 the game. Progress for Series 12 still not saved.
I'll try fiddle with more settings.
Log attached.