Spray-on foam and a sandblaster instead of a smoke wand? Maybe you could spray the foam wet and left it solidify in the wake.
I suspect the reason the picture that appears on the laptop in the 40 minute video shows so much symmetry is that the car is down in a street grid that channelizes the air so there is no gusting, and the car is parked nose into the wind.
http://ecomodder.com/forum/showthrea...ure-11745.html