I can't speak for th 4900 series, but I have an '04 4500 and an '06 4500. Yes there are different components on the bikes like wheels, brakes, and crank. I personally haven't noticed enough of a difference in feel from one to the other to mention anything. And the parts move had to be fairly lateral since the overall cost of the bike didn't change much. I would think that this line of thought could be applied to other bike series as well. But I could be wrong.