That flywheel of Steve's looks familiar

You can't buy those flywheels. They were made by Endurance Racing for HRC and only available to people "in the know". It's for a MC28 and was developed for the Asian Championship when rules said we could alter the ignition system. I had one fitted (maybe even that one

Endurance even made one for the F3. Obviously a lot smaller and lighter, and a lot "BINGier" that the one in Steve's picture.