sirtigersalot

noramally the brakes come with all the adapters you need for the rotors they come with, however i assume you arn't getting this new or somthin cause they don't come with g3s

anyway you need 185 caliper mount in the back, and the post mount adapter for the front (which is basically just a shim and longer bolt to get the caliper further away for the larger rotor)

you will need new cables and new housing (old stuff not long enough, discs are futher away) but you can use the stock ****** brake levers, you just wont get the full benifit of the upgrade until you ditch that crap

you should also be aware that many forks that use a quick release (like i'm sure ur rincon uses) don't recomend using larger than 160mm rotors, i've been told the reason is that A on an xc hardtail 185s are overkill, but more importantly the xtra torque of a larger rotor (especially a 203) can pull the wheel out of the drops, however plenty of people run large rotors on qrs and many bikes come stock with 185s (or even 203s in rare cases) on qrs, so i wouldn't worry, just make sure your qr is damn tight

oh and you said u have disc mounts, i assume you already did this but still have to mention: make sure you have disc compatible hubs (6 bolt holes on the non-drive side (left) of the hub)