Get ahold of dan (acutemp on drn). He's running (or has recently) a 39mm on his modified 200. As I recall, the larger body PWK did indeed fit into his kdx without too much trouble. Maybe it was not trouble a'tall.
Carb modification to the small body PWK is avail thru R&B Designs that will (among other things) bore the carb to 36mm. That's a bigger step on the 220 than the 200, but good for both. Search for 'carb mod' on this forum for a gazillion (should be) threads on the subject.