Other items needed:
HTD 3M 9mm belt and pulley (obviously). The pulley is 14 tooth, 3mm pitch, 9mm width, 5mm I.D.
(4) M3x20mm bolts to replace the existing M3x16mm bolts that are now too short.
If you have the wavy/flat washer bed leveling system, you will need to add one of each washers on the third bed leg to make up the height.
(2) extra 624-2RS (4x13x5) bearings to add on the belt idlers to make them wider. The existing bolts are already long enough to accommodate the extra bearing The belt doesn't really ride on the 3rd bearing, but it's close, so better safe than sorry.