I called Alcan and the springs will work for 2 wheel or 4 wheel drive vehicles. However, there is a difference in the bushings between the regular cab and extended cab so the springs on ebay will only work on the regular cab.

Bummer, as I would have bought them otherwise.

96 T100 4x4 - 35's, 4" SL, 2" BL, 4.88s, ARBs, custom bumper & E9000 winch, etc.
99 F-350 4x4 superduty supercab turbodiesel longbed