Yes, but those are relatively minor adjustments. If the 54 v 56 is the question, you need to go sit on some bikes. To illustrate, I have a 56cm Roubaix. I would not really be happy with a 54, regardless of what is done with stem or seat adjustments. Might work to get me from A to B, but it wouldn't be nearly as good as the fit with the 56 frame.