Comment before reading / watching:
I just finished my son's Cub-based version which is in essence the same thing, but with marginally different rules. After abiding by what was perhaps too strict an interpretation and helping him only where it was in the interest of his safety last year, he was absolutely creamed by some creations that had all the hallmarks of not being prepared by 7 and 8 year old boys but their fathers. This year I took a different route all together and leaned on all the resources at hand - a rocket scientist friend of ours (mine), a budding aero researcher, more than a few YouTube videos and lots of plans for R&D (that never matured beyond plans.
The rules for his car have specific dimensions to ensure it fits the track and doesn't interfere with the other cars, a max length, max weight and a brief but fairly inclusive "no bearings, no bushings, no washers" rule. Given the nature of the competition, rolling friction seems logically to play the biggest role - wheels that run parallel to each other came up a number of times.
Despite the prep, the execution suffered. I had concerns all the way along about how I was going to successfully build the side pods as drawing them with a .100" thickness over the top of the wheel was easy while keeping them from breaking was another matter all together. It doesn't help that as a woodworker, my incompetence is exceeded only by Homer J. Simpson. Maybe. In the end, the car raced without wheel covers and several ounces of lead weights covered by epoxy and what can only be described as sub-optimal wheel prep.
I carefully deburred the "axles" (nails) and wheels, removing any flashing lines and reducing the surface area that might rub between the wheel and the body. And then I lubed them. I eschewed the established advice of using sewing machine oil or dry graphite and instead used a molydisulfide / graphite spray lube. Something in the product softened the plastic in the hubs and rendered them useless. This of course was not apparent until they'd been installed. It goes without saying this all took place perilously close to the race start time. We purchased a new car kit (cheaper than buying 2 sets of wheels that are sold in packs of 3), hastily installed them as best we could and ran it.
He didn't win - that honour went to a brick with properly prepped rolling stock - but he was very competitive and landed in the top 5 and left with a huge smile, the ultimate goal given the tears of the year prior. Next year is his last round before moving up and racing trucks so we've got one more shot. This time we'll focus on the wheels and add it to what we learned.
His car is #7 - shown with other cars for scale. The #4 pink LEGO brick took all the winning. Speedy thing.
Painfully close, but his final race as he got spit out the back by an alligator.