How often are you changing fluids?
 

For my old Miata race car, I was changing diff and trans fluids every other event, and oil after every event (usually a 2 day weekend).

How often are you all changing fluids; specifically engine oil, trans and differential fluids?

diff and tranny every other oil change. oil change every 3000 miles regardless of how many trackdays.

3k engine oil
30K for dif and trans

unless one of them gets over heated.