Sherod -
no question that the sound is improved - 100%? - probably not but I was lucky enough and had smart enough advisors that it enhanced what was already there - it didn't change the character of the speakers - in other words there was no startling now you hear it, now you don't kind of moment.
I suspect the main reason for this was the attention paid to everything that went in the crossover. To Sns point, it takes really good parts to improve on a good design.
I got my moneys worth and more out of doing it. Sourcing everything, creating a workbench, consulting on the parts, learning how to do it - that was all tremendously satisfying.
The fact that they work, much less sound better is just a bonus LOL