OP out of curiosity, do you find that when you press the pedal when moving - take your foot off the pedal and then quickly press it again that it firms up?

If so, I have a nearly identical scenario going on with mine post TBU.

Just for documentation purposes, I went with the PowerStop KC2324 Z23 daily driver set up with Rotors, pads and calipers and StopTech 95044007 lines.

FWIW With this set up, the rotors were thicker (but same diameter as OE), the calipers larger (had to trim dust shield) and in turn the pads were larger as well. (I am not sure if this set up was 13WE or WL if I am being honest)

It stops. It will stop short. The shudder from the original warped rotors is now gone. But the OCD in me knows the pedal was firmer on the OG set up then it currently is, aside from quickly pressing the pedal the 2nd time when braking. That seems to have a more original feel for me.

That said, I am going to anxiously follow this.

I chalked it up to mine being an 01 with ABS and some people just seemed to have a different pedal after the TBU and dealt with it. I'd love to get to the bottom of it myself.