We recently had someone reach out to us after doing this sort of comparison. He owns a pair of smaller Wilson towers, and a buddy brought over his Wharfedale Diamond 9.1s with out kit installed to compare them.
The upgraded 9.1s smoked the Wilsons in every metric (clarity, soundstage, imaging, separation, etc) other than dynamics.
This may not always be the case for every speaker we offer upgrades for, but there is always performance being left on the table with 99.9% of retail speakers, even a lot of the high end ones.
And we regularly get a lot of great feedback from our customers, at how much more they're getting out of their speakers that they had never heard or experienced before.
Of course, physical limitations of certain drivers/designs can & will still come into play, so heavy aluminum woofers will still lack some finer details compared to a similar, but lighter, paper cone woofer.
That said, the better the bones of a given speaker design and it's drivers, the more it will have to give, when using high-quality networks.