in reality...we dont' have TORSION bars... well they are sorta...but not in the reference that you are making....they are sway bars....but yes they use tortional stresses to work.
lostening your torsion or sway bars will NOT lower your car....our cars do not have a suspension like the old VW beetles where the torsion bars actually supported the car....OUR torsion/sway bars are an inactive part of the suspension that help reduce body roll. nothing more. the struts and springs support the car. so if you want to lower your car.....its a set of springs and the proper struts to go with them to do it 100% correct.