Novice

Is the exhaust system (ie the entire pipe system) of the XT660R stainless steel? I know this is pretty basic question, but I don't seem to be able to find anything on this - not even from Yamaha spec sheet. I know the chassis is steel. Does it mean it will rust away if left outside? The TDM900 is great - aluminium chassis and stainless steel exhausts, great for someone that can't afford a garage (living in central London).