Brendan, the GT-R upgrade may be the one to go for using the following formula:
bang for buck/hard road use*, where *=no. of track days
otherwise, the DBA 4000s with Ferodo DS2500 or Pagid pads (as recommended by DBA) and good quality and condition brake fluid and braided lines may be fine.
I tend to agree with Roy, consistency is as important as outright stopping power.