I built a second car to try something out...
Improve body rigidity installed
Increased front compression to 4
Increase rear brake balance to 6
Increased rear anti roll bar to 6
Initial torque reduced to 8
Rear downforce reduced to 105
These changes have seen lap times drop into the 1:54 second bracket online and a new PB Total time of 5:49.526
Improving rigidity seemed to make the car more stable and built confidence to make it a little more aggressive
This modification can't be undone, but when a race can pay for a new car it's worth trying