So far, besides the normal consumables (pads, rotors, tires, oils, etc.) the only thing that I have already had to change are the front wheel bearings.
Given the (poor) quality of the roads in tri-state area, I am not sure if I can really blame this on the track usage.
Other than that, rock solid car @ 60k miles. (knock on wood).
Another recommendation for everybody to save a few bucks: disconnect the break pad sensors when going to the track because the heat is going to weaken the plastic parts and will end up making them very brittle (i.e., you will need to change these more rapidly). Just zip-tie them to the break line or somewhere.
Also, a heads up for you guys who like to DIY the maintenance: I believe that due to the severe heat cycles that result from the track use, some of the components such as rotors, wheel hub/bearing, etc... end up "warping" a little bit and they can be tough to remove from the car. Dont ask why I know...
--> At this point, I would probably receommend that you buy the extended maintenance coverage as the parts + labor add up quickly.
Background info:
bone stock car / Pagid Yellow pads / Yokohama AD-O8s (255 X 275) on 19" wheels