I think they are just "special parts" but there's quite a few of them.
Aoyama's factory 250.
Rich G's NXA
Even from the photo you can see a different frame, swingarm, forks, brakes, engine, wheels, fairing.
Plus they're jetted perfectly for the day and had a top end that morning.
I don't know what sort of power they're making, probably not 120bhp, but you need well over 100bhp to do the 170+mph they did.
This is the only graph I've seen, allegedly a 2005 works Aprilia, over 90bhp for 2500 rpm....
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