on my aftermarket wilwoods, i had the rotors cadmium plated. the surface where the brakepad makes contact with the rotor is okay because you can just use the brakes to get the rust off there, but the rest of it is rust-free
i don't remember how much, but it cost me less than 100 bucks--i think it was about $60-- for both rotors (each rotor is about 13" x 1.25")
anyway, i brought it to a place called "Manco Plating, Inc." in Newark, NJ.
once you cad plate them, they will not rust where the plating still resides. but after the initial coating, your braking will be a little weird because the pads make contact with the coating. once the coating near the brake pad portion is removed, it brakes like normal again
ok a really easy way to kep brakes from rusting is use them. also with the nice wide open style of rims that come with the tC you could just wipe them down while your cleaning the rims. the problem with a car that is heavy like th tC is after hard braking, like if you do it ALOT, is warping, but that could just give you an excuse to buy a nice set of slotted discs, and those are off the heazy
the amoun of brake dust created depends on what kind of pads you have and how frequently you use your brakes. unless rotors are specially coated, they will rust over time, but like thornless said, you can just wipe it off.
depends on how bad the rust is, water may not help.
i would recommend something like a brillo pad to wipe it off with; somethnig that is a little abbrassive, but not too abbrassive.
rusting occurs due to oxidation; since water = H2O, it can cause oxidation too, but also realize that the oxidation process takes time, so it's not like spraying water on metal will cause it to rust instantly hehe
i just recommend not worrying about it. they will still stop you and it wont be that noticable. many other things to wrry about than that. And if you dont drive you car enough that the rotors rust to a point that they will sacrifice peformance, well you dont desirve to have a car. YOu are doing it an injustice by just litting it sit