Is your 220 stock? If so you will only see a marginal gain by installing reeds. Aftermarket reeds typically flex easier and give a better throtle response but no huge performance gains. Now if you have modified the exhaust and removed the air box lid you probabaly would be well advised to get the reeds. I also agree the Boyeson reeds are the best bang for the buck.
Since you have uncorked your KDX a set of reeds might be a good addition at this point. Your right there are Boyeson PRO reeds that will work just as well as the power reeds. A RAD Valve will set you back $150 or more and that money would be MUCH WISER spent on having your carburetor modified by R+B or Fredette.