480 forks & clamps & front wheel are the go if you don't have to put up with rulebook racers. You will have to find an RZ/RA steering stem or shorten the 480 stem to fit the RZ chassis. Convince me there's a significant performance advantage between YZ465H forks (evo legal) & CR480 forks (not legal) and I'll shut up, otherwise it's just utter BS!
Cheers,
K