You will find numerous threads in this section dealing with BBKs. In most of them a lot of people suggest that upgrading pads, switching to DOT 4 fluid and SS lines is sufficient for most track use. If you are running on short tracks with a lot of corners close together then the next step would be a front brake cooling kit.
Be careful as some BBKs require an upgrade to 18 " wheels for clearance.
The best way to improve your braking may be to get better tires
An econmical choice if you decide to upgrade is the GT500 FRPP Brembo upgrade kit.
Be careful of drilled and slotted rotors. Drilled rotors can crack if not properly made and slots can decrease pad life if not done properly.