Keep in mind I have never driven RA, I'm probably talking out of my ass. If so, please correct me.
The Porsche is angling in at first, the wheel is straight. If you watch carefully, you can see it start out straight, then turn left. The DW driver was sticking to his line, the Porsche was the one all over the place.
Early in the vid from the car behind them, the Porsche is to the DW's right coming into a left turn and looks like he's on the race line (the dark line on the track), then goes across the track to end up on the DW's left in a right hand turn, in the process cutting across the DW's nose. That's what I would call not real good line selection. When I looked at it again, honestly neither driver was in a good position or truly on the racing line at that point. But there was no contact.
The DW hits what I would consider the correct apexes of both the left and right hand turns even though he seems to have come in too far to the left in the left turn, then continues straight up the track at approximately the middle (leaving plenty of room on his left for the Porsche to be between his car and the bridge) and that's when he overtakes the Porsche, which by this time is on the rumble strips. Immediately after that is what I call the 'overcorrection' and ensuing crash.
I'm not so sure the Porsche driver wasn't pissed at the DW's driver for the shenanigans in the left hander, then decided to teach him a lesson. That's not good.
As far as being passed by a 'non classed' car, so what? Why should that mean anything? That being the case they are not racing for position, unless this is like LeMons wheneveryone is racing for first regardless of how you are classed. (Oh, yes he DID compare these to LeMons cars! )
When I was racing hare scrambles, my class was white numbers on a black background. If another bike near me had a different color combo, they were not in my class therefore it was pointless to race them unless they were slowing me down. A pass meant nothing, position wise.