To add the the topic, I purchased brembo discs for ~£80 each. No issue with performance, however they aren't treated and look a bit nasty, see picture.
I don't ever recall seeing this with the Lexus discs which were removed, so I assume genuine Lexus discs are treated. To confirm the fronts look ok, the the rears look nasty and I'll be replacing them with genuine Lexus discs next time.
EBC yellow stuff pads work a treat though! Very happy with them.