In my books there can only be so much point in modifying the bikes suspension and brakes before you find the power is well down, the 500 is the earlyer of the middle weight sohc bikes, if your headed the way of wanting to upgrade things I'd start with a later 550 or even 650 as all the upgrades got added by honda so less things to source for a very similar bike. You'll end up quite easily spending double the bikes starting value on brakes, forks, clutch and cam upgrades etc before you ever saw any benefit to a better rear brake. The frame would at that point probably dissapoint...........