A couple of things about the 220; first, it does NOT have power anything like a 250 at any engine speed. Trust me, I've been there and done that. The truth is, that a 250 will shred the 220, even if the 220 has port work. This, however, can be a GOOD thing; a 250 can be a brute in the woods, whereas the 220 can be more co-operative.
Second, forget all those fears about racing the 250's. In MN, we have some fast woods riders. In the C & B classes, the fastest guys are typically aboard 200's and most often 125's! Often times, these guys are fresh from the mini classes, where they've been shooting roostertails for the past few years. I would suggest to buy the 220 to get away from those up and coming young hot shoes on 125's. Besides, if you feel a 220 would be more appropriate for you to ride, then ride one and forget the score card.
Now to the original question... If you search this forum, and check the JustKDX site, you will find a wealth of info to help you decide.