Hi 'demon,
scroll down to the list's classifieds, you'll be amazed at what you can find there.
MikesXS has a vast range of XS650 parts, I'd be good with buying anything made of metal from Mikes,
anything elastomeric I'd first try to get elsewhere.
Heiden Tuning is another good site to browse through.
Can't say about TCBros, I've never dealt with them.
Mike (Mercury) Morse's 650 Central can be really helpful but recent posts say the site has recently gone dark.