I changed to yellow stuff pads when my standard ones wore out. They do give improved performance on track, but they arn't as good for road use. They must need a bit of heat to get them going. I also have a set of the pads Brian had made up, but am yet to try them.
If improved track performance is your aim, try EBC yellow stuff pads. Some have done bigger front brake conversions, but it's not an easy task, and i think requires wheel changes too.