I believe the Willwoods are not that good.....

The 2wd calipers are heavy cast iron 4 pot calipers where as the 4x4 are large diameter single pot calipers which creates extra clearence around the spoke area but then don't fit straight on as they need modifying where the disc runs through them....The 2wd calipers don't fit straight on either as they need brackets and then I don't know if they will fit behind the wheels.

The easiest upgrade is a set of caliper spacing brackets, S2 calipers and 2wd Cossie discs...