If I may make a potential suggestion, would it be possible to have a number beside the "limited" icons as well as the "unlimited" ones, to show us how much we've upgraded an option?
This is what I am referring to: the red circled ones are the "unlimited" ones, and they have a number beside them showing their level. The yellow circle ones are "limited", so my suggestion would be to have a simple "9" underneath the armor icon (which is maid impenetrable), showing that it is currently level 9. The same would apply to the purple/white star (core enhancement), the book (spell upgrade) etc