Our Granite is bad about that. But even after letting off the gas, turning sharply sometimes sends it cartwheeling. But the Granite is like a cat and slmost always seems to land on its feet.
A lot of buggies are that way because they get better grip in the corners than the center of gravity can withstand. It's all about throttle control with buggies. Practice and suspension tuning will help.
A good practice is to try to ease up on the throttle every time you turn the wheels 😉
That is a cool looking rig! ZD Racing makes 1/8 scale shocks, but not sure if they have the length you need. Measure from eye to eye and see what the lengths are front and rear.