Kind of funny, but you might consider getting a refurbished ThinkPad from a couple of years ago. If you're ready to replace some parts, a T440p will be fast and good for years to come.

I got my X230 and it's so fast I really question the need for the new CPU generations...

From what I can tell, Thinkpads are in a slow decline. So it's not so much that I expect to buy a better one, but that they'll be about the same as everything else. If they aren't already.