Neat video. For those of us without the background, the only thing I might add would be a quick summation of whether your experiments supported or contradicted the manufacturer figures (because maths). A simple, "Toyota said this; we got this. This is within/outside normal error." It's interesting to see the 86 seems to get slipperier at the higher speed - if I'm watching the video right. This seems to support my personal experience that I get excellent (and potentially better) mileage up to the mid-seventies.
I'm also curious, once the spoiler is added to the 86, the lower bubble gets bigger but the upper one seems smaller (compared to some of the other vehicles where the bubbles changed size in general but still seemed to stay relatively symmetrical). Does this mean anything?
I seem to recall reading the fully-aerod 86 is within .01 of the Prius so while building a Prius model might not be as exciting, I'd be curious to see if that was true. I had an '87 Celica and I also remember reading it had an impressively low CoD for its vintage - I do know I could get 40 mpg on the highway and regularly maintained 35-36 mpg avg. It'd probably also be interesting to throw a Tesla Model S into the mix. If it comes down to only one one-hundredth of a difference in drag to have something that looks like the 86 or Tesla over something that looks like the Prius, I think the case is clear.
From a model-building perspective, and not to criticize, but the paint jobs seem very rough; I'm curious whether that would effect the boundary layer separation in these tests. I would think a properly prepared surface and glossy black would better represent the actual paint job.
Lastly, I might suggest the production could be tightened up a bit. I suppose this is being presented in a manner required for scientific rigor, but after the first test for example, I didn't need to be reminded how the bubbles worked, which direction they were coming from, when you switched from constant to pulse, etc.
I still really enjoyed it though. Thanks for taking the time to make this and I look forward to the next segment!