Heatshield
Because of the close proximity of the exhaust header to the clutch hydraulic line, the heat of the header can cause the fluid to boil. This will be noticed while driving the car as you seem to loose clutch adjustment and it becomes more and more difficult to shift. When the car cools down the clutch will return to normal operation.
One thing that can be done to help, is to install a heat shield as shown below. This modification is easiest made with the engine out of the car. With the engine in the car, you may need to find another way to attach the shield
Other Related Tips
UPDATE! Click this link to install with engine in car
Change all brake fluid after two years or 5000 miles or before any track event.
Use a Dot 3 or 4 Brake fluid with a dry boiling point of at least 500of .