Not if they crash into stationary objects like rocks, etc. In that case the amount of force the driver will experience will be 2-3 times higher compared to the amount of force a driver of a normal sedan will experience if he had the same accident.
this is not true, the deceleration (g force) imparted to passengers should be the same in either case. (all other things being equal, initial speed, crumple zones, etc). adding more mass to the car is irrelevant to the driver if you’re hitting a truly immovable object.