Headset, with the mods you've made, a rejet at your current altitude should make a significant improvement. And when you move to NM, you'll probably need to drop the main down a bit more. Maybe the pilot, too. But...I don't have any experience on the 220. Check Candian Dave's JustKDX site for suggestions.
Recommend that you gather up a list of mains, pilots, and needles that look promising. Then place your order with Sudco. You'll save a ton of cash vs. Kawasaki parts and have a much better selection of needles. A fair assortment from Sudco will probably run you about $30 to $40 (or more if you order a bunch of needles @ $5.25 ea.).