Car getting unstable while being at/ braking from high speeds

[Da_eevee]

Ive got a 3000hp lancia stratos (dont ask why) and for some reason, as soon as i reach the 180mph range, the car becomes extremely unstable when braking and/or steering. Example: left kink in straight before final hairpin in New York. The car starts turning, then it seems like the whole weight shifts to the right making the car slide out of control. Pls help