sorry, but that's not frame twist, the body is straight as can be, if it was frame twist the back would be more level. we can see the full roll cage through the windshield, it should be mounted to outriggers, and the out riggers would be tied to the inner rockers, the roll cage is stopping most of the frame twist.
it's the lack of a properly adjusted three link set up, the right rear tire is flattened out until the rim is almost touching the pavement, and the tire is pushed way up in the wheel well with the shock almost totally collapsed, and the left rear tire is almost off the ground because the shock is at full extension. the rocker panel on the left side must be higher than the top of the tire, while the right side is almost touching the pavement.
an anti-roll bar in the rear would be the first addition I would make, or better yet a fourth link. also the car is begging for a little heavier springs in the rear.
and if I'm wrong and it has a 4-link set up, somebody needs to learn suspension set up.