Tangent, but my son and I used Mark's video on building a pinewood derby car. He gives a list of 7-8 things to do to your car in order of effectiveness. A theme in his video is that the car doesn't have to look fancy to be fast. We implemented most of his recommendations and didn't have time to paint or decorate the car. We ended up winning and we were the most unadorned car in the pack.
I built an aluminum forge and made some castings following one of his videos. Only about ~$50 worth of parts needed (and $100+ in safety equipment to be safe)
TLDR: Mark is legit.