Question

Is it still possible to get the Rabbi’s “quadrilogy” in physical copies? (I know there’s probably a proper technical term for it, but I liked the one I came up with better.)
Also, is there any point in reading the quadrilogy if I’ve already read the trilogy and the Rabbi’s other three books published by Yedioth? Are there different things there, or is it basically the same material?
Underlying the question is the assumption that the Rabbi will be honest enough to tell me there’s no need if that’s really the case, even though the Rabbi has a financial interest in the matter.
I really enjoy the Rabbi’s books, but I don’t have much time to read—only a few hours a week—and that’s why I’m asking. Thank you very much.