I did a pretty good accounting for costs from last year here:
http://986forum.com/forums/boxster-racing-forum/41688-yearly-track-costs-how-spend-%2420k-yr-%2410k-porsche.html
Since I published that list, I've replaced the spark plugs, all 6 coil packs, and I am having the the top replaced today (Robbins glass window).
Previous to that list I've replaced the AOS, starter, rear wheel bearings, rebuilt/repacked CV joints, transaxle spider gear, clutch, throw-out bearing, flywheel, major service, spark plug tubes.
I have a water pump, 160F thermostat, and the Boxster S oil cooler sitting here ready for installation this weekend.
Looks like us 986 owners are doing more than our fair share to re-vitalize the economy!