Best pads I've used by miles, (for track days & road), are the Ferodo DS2500's. Unbelievable bite..... They even worked well from cold (even better than standard pads). Sit down for the price!
If you don't want some as hardcore as that, then try the DS2000's (just called DS's now, IIRC).
Alot of people on the GTi-6 forum (who do lots of track days) have been a bit disapointed with that Black Diamond set-up (& also EBC stuff).
Also bare in mind, that drilled/grooved discs will wear your pads out quicker than solid discs.