Wet sanding is not the end all but is good for a few reasons,. It reduces dust in the air, lungs, eyes, etc. Increases sandpaper longevity, and highly important in my book it reduces the possibility of particles getting trapped under the primer and paint. Speaking of paint, if you elect to pro paint you'll definitely want every spec of dust removed from every crack prior to even priming. Other than that good ole (non wet) sandpaper works just fine and 400 grit is highly recommended as it provides a good bonding surface with the primer and paint.
Hope this helps