Ed,
If you plan on riding the bike to the limit, Motul 5.1. The 4 stuff will boil and fade halfway through a race. I change brake fluid every other race and it is impressive to compare the old vs. new. If you think about $7 bottle of brake fluid the $20 for oil changes, and the $20 for the race gas, probably doesnt compare to what you spend to travel, eat, etc. for your riding time. Some people operate in a false economy. I prefer to buy sandwich meat and bread and save the "Happy Meal" money for the stuff that really matters. There is my $.02 worth.
See you on the trail.