Hello matey - i am no mechanic, but when i have chatted to my biking buddies about buying bikes, they have said it is not so much the wear and tear on the engine, it is the wheel bearings, linkages, suspension and other peripheral parts that wear out first. 22.5k sounds a lot - too high for me - but if it is fully serviced and in good nick, then why not!
This post was probably worth nothing of value to anyone, but i enjoyed passing on the advice that got me to buy my new R6! tee hee.