It is my understanding that registered users can use the search function. I suggest you try it, as the first question has been posted many times already.
My 'mileage' has varied from 26 to 80. It depends.
As far as the second question, try the search function on that, too.
Some riders do...some don't. Basically, if you want a track bike, buy one (the kdx isn't a track bike). It will 'handle' ok...meaning the wheels won't fall off or anything.
But then, I don't have a 220, so I'm not qualified to answer your question, 'eh? ;)