Metal Tech 4x4 FJ Cruiser stage 2 rear long travel suspension kit. Metal Tech 4x4 after a year of testing has finally released our custom rear long travel suspension for the FJ Cruiser. Metal Tech 4x4 designed a unique progressive rate spring that has a free height of 19 1/4" while still maintaining a 2" lift. The bottom half the coil is rated at 250lbs of spring rate and the upper portion is at 105lbs of spring rate. With this combination the spring can stay in it's compressed position at ride height and expand out to it's full free height on down travel.