Direct from Unplugged Performance's site on their brake upgrade kit:
A NOTE ON BRAKE FLUID & HIGH PERFORMANCE DRIVING:
Brake fluid plays a vital role in the performance and reliability of every brake system, especially so in high performance driving. A professional brake bleed with high performance fluid is a requirement for the functionality of our brake system. We recommend using Motul RBF 660 (our go-to fluid) or Endless RF-650 brake fluid. Brake fluid should be flushed frequently for race cars in particular because over time moisture content builds and moisture inherently decreases the temperature limit of the brake fluid. Brake fluid and the temperature capabilities of it matter especially due to the high temperatures the heavy and powerful Model S generate. The higher temperatures seen in the brake system transfers heat to the brake fluid and when brake fluid boils those bubbles create air in the brake lines. Air in the brake lines from boiled fluid can create near instant loss of brake pedal. Therefore, using a high temp brake fluid and managing brake heat is a key to safe braking for extreme environments. Loss of pedal is a different symptom than brake fade and typically a symptom of brake fluids exceeding their temperature range (or alternatively a leak in the system) whereas brake fade is often a byproduct of the brake pads exceeding operating temperature range. In both cases managing temperatures in a racing environment and adequate testing is typically found in motorsports drivers and always strongly encouraged to get the best and most safe result. We flush our brake fluid after each race and we monitor caliper temperatures for these same reasons on our race cars. Please always feel welcome to talk to our team if you have questions about motorsport use. For street driving the temperatures seen are significantly less and this plays a lesser role although the same fluids are suggested for street cars as well.