You Will need to balance the crank with your 2wd flywheel, but you can keep the 4wd one but its heavier.

Your cr Will change so an adjustment of the map is recomended.

Use the 2wd mounts, headbolts is the same, you can switch pulleys to suit your desired belt although crank pulley may be an idea to have balanced with the crank aswell.

Its quite a straightforward swap otherwise.