Chelsea Clark spent more than two years and who knows how much money working on the EFI and engine management for TAD when it wasn't legal to run.
Once he proved the concept he submitted it for approval and it was granted. That's how this stuff works.
Don't remember the exact time but a few years ago Jim Head was testing a Carbon clutch. Instead of sintered iron discs and steel floaters, it was Carbon on Carbon. It also wasn't legal in competition, but if they proved it was feasible, they would submit it for approval. That experiment didn't work, so it was dropped.
You might be surprised how often things are tested that are not legal, but often that's how you prove what area to go to work in.
Alan