What do you think the cause of the Panoz at the ALMS race on Belle Isle?

It seemed to me that the car was coming loose by turns 4-6 (where I was sitting) towards the end. I don't recall the car pitting for tires, and I don't know if they did a driver change. So was it driver fatigue? Or a need for a new set of tires?|||The cause was most likely tires. The whole track seemed pretty slick, I watched on The Speed Channel.