The caliper will be fine. The axle diameter on the WPs is different. WP uses a smaller (20mm I think), Shivers is larger (25mm I think). You'll need a axle from a 2004 or newer bike, axle nut, wheel spacers, bearings, seals, and the spacer between the wheel bearings. The hub is fine, the I.D. of the bearings changed when they went to the Marzocchis but the O.D. of the bearings stayed the same.