OK OK i do belive that the purpose of a wheele bar on a FWD car is....
1) With out a wheele bar and u have full slick with low tire pressure when u go to the line and u decide to launche the front suspention lifts and the rear sags causing less traction in the front
2) Now with a wheele bar it eleminates this by leaving the wheele bar off the floor enough to turn by it self(rules) its just about enough for a quarter flat on the floor to slide undreneath , so what it actually does is when u launch the car the tires lift sending weight to the back by doing so and having the wheele bars since they are stiff it does not let the car sag in the rear keeping the car weight to the front
And it has nothing to do with fliping the car over
just my .2 cents