If you look carefully, the Corvette came across the front of the Porsche, you will see if you watch videos of it, that the Porsche didn't even have any damage at the front. If you think ramming someone in the last turn to gain a place is acceptable, then a pit maneuver is also acceptable.
All the drivers could've challenged Rob Huff for the win, but instead they all slow eachother down as there is a mad scramble for 8th place (and pole in race 2), I've never seen drivers trying to force others to overtake them before.
A more modern video though; Sebastian Vettel in his pole lap at Albert Park yesterday. Watch for the handful of oversteer in the last corners! Fabulous.