Philipt,
Aren't you going to cover your primer with a finish coat of paint? Wet sanding 2k will work, as long as you don't go through the finish, but it sure won't leave the proper "tooth" for you final color coat.
Dry sand with something on the order of 320 or 400 would probably be more than adequate...unless you are going to run the rig down the road in primer.
The final color coat needs something to hold on to. That's how I see it.
Stuart
