If I put a 10.5 in my FGX or even F104 I would wreck that shit.
I did however run an 8.5 at about 80% in my F103 on foams on both asphalt and carpet and that thing was nearly untouchable during last years UF1 Series that gave us the choice of running either "Realistic"/current F1 cars on rubber or "Open"/any cars on any tires.
I chose, and would choose again, F103 on foam tires. Nothing comes close.