All the two-car transition teams have four tubs and the one-car efforts are supposed to have a pair of Dallaras. The catch is having enough parts to assemble all your cars.
Pfft. Details, minor details!
As for why this is, in fact, a problem, this via T&S:
Yellow for contact near pit exit by #96 Mario Dominguez. He spun coming out of the pits.
Ooops. Then again, despite having some ability, that's not the most surprising incident ever.