You can install roll cages in some vehicles: not only is it safer, but it improves chassis stiffness and vehicle handling (use [action=parts_selector]).
Operating an engine upside down causes oil starvation. Blue exhaust smoke will occur from oil submerging the cylinders, and the engine bearings could fail.
If a vehicle starts fishtailing from side to side, you need to countersteer earlier and faster. Using a steering wheel (or gamepad) is highly recommended.