Ive read torsion bar keys can lift a truck up to 3" and still have a stock ride and others say it gives a harsh ride since all it does is crank up the torsion bars. Whats the deal? My cousin is looking at getting a 2001 2500HD 4x4 Diesel crew cab. He would like to run 285/75/16 or a 285/70/17, or maybe a 33x12.5 tire and doesnt want to spend over a grand and lift the truck 4 inches. Any ideas?