I switched last year from old MP-32's to JPX-825Pro's and been very happy with them. MP-59 would have been nice too, but I liked the added forgiveness of 825Pro longer irons (playing off 5).
I'd recommend going for a fitting session to try different heads and even shafts.
Btw, I got mine from the factory with custom lofts and lie angles as well as progressive swing weights (1/3 SW point increments from 4 to P, most they were willing to do) at no extra cost. Not exactly MOI matching, but step in the right direction that's worked well for me.