Had my first track day with my 17 GS this past Saturday. Five 30 minute run sessions at PBIR in Jupiter, FL on a relatively cool day (ambient max's at around 75). Sessions were spread out from 9.30am to 5.30pm with plenty of cool down time. Everything was fine at the track, pressures and temperatures. Car ran great! On the way home from the track, the check engine light came on. Stopped at a gas station, fluids all fine, temperatures and pressures OK, no noises. Scheduled a maint appt for Thursday am. My wife took the car out for a quick spin today, she didn't get more than a minute down the street and all hell broke loose. Very loud banging sound from the rear of the car. She immediately crawled back to the house and parked it. Anyone out there have problems after a track day? Sounds like the rear diff? Thanks!