I doubt you want to hear this, but I wouldn't do much w/the brakes.

I use Cobalt Friction VR pads on the track, with OEM calipers and OEM or Brembo blanks...everything works fine. These are the same Cobalt Friction compound that just won the 24 hours of Daytona.

For what it's worth, in H2 Honda Challenge, which doesn't allow brake modifications, the ITR brakes are renowned as unassailably the best available in Honda Challenge.

I have never had a problem with stock ITR brake systems on the track.