Tuning The C7.R (Does anyone have an idea how?)

United States
York Virginia
I've spent the better part of two evenings trying to get the Vette to stay planted while turning.
I have managed to get the brake balance corrected. But its very unstable over curbs.
Around sweeping corners, the rear end gradually breaks away. Same for braking while turning in.

Adjusting dampers, ride height and spring rate did little to help. The car is not as fast or punchy as I thought it would be either. Kind of sad that the C7.R does not perform up to expectation.

It certainly could be the fault of my tuning. So does anyone have suggestions?