Lightening flywheels not only lightens whole bike, but also improves acceleration remarkably, 2 birds,1 stone (14lbs
) I know from previous statements to this effect on this forum that there may well be some more discussion.
Grey Flash Girdraulic legs have milled scallops inside I believe. The info is freely available. I would shot peen them after doing that mod to ensure no loss of fatigue resistance.
I have been looking closely at cast steering head lugs recently. I would consider fabricating one, and the swing arm casting also, but probably not what you might consider as low hanging fruit.