I would also imagine the X plus being a good bit heavier, think the 8 plus is 202g or so, expect the X plus to be 220g+, this might not seem much but i had the 7 plus which weighed 188g and you do notice straight away the extra weight coming from the 7 plus, so anyone upgrading from a X to the X plus will be shocked at the weight difference, X=174g X plus=220g+, that's 46g or so, believe me that is very significant.
I wish the next X goes back to using aluminum so the weight can at least goes back to iPhone 7 weight.