I have a 1957 chevy pick up that I will be narrowing the rear for 20x15 wheels, Can any one tell me is there a big difference between the airride bags(the bags with the shock that goes threw them) and the older firestone air bags, I know the airride is a cleaner look to them, but the price is quite a bit more.Also can anyone recommend a 4 link system (the best bang for the buck) so to speak. Thank You.....Mike