On the topic of speed... used to work with a guy that had been 4A HS coach, had won a state title back in the 80s. His son played HS football very successfully at a pretty high level, and went on to play at Coe as a CB. Parents had connections at Coe.
I was talking to the dad, and asked him what is the difference between son going to Coe vs say Iowa or ISU? Size, speed, what? And he basically said if he was a few tenths faster then D-1 would have been an option. It was that close - just boiled down to running maybe 0.2 faster in the forty.
Speed kills.