Belts plus valve check is about $500 at 12k. You should change the oil and filter, check the air filter, check the fuel filter, flush the brake and clutch fluid, check the coolant, check the brake pads, check your sprockets, and... that's what I did before the 12k service... well, except for maybe the fuel filter which was the cause of my overheating.
I would state specifically that you want them to call you if they find anything unusual so that you can decide to do it yourself. They usually call to tell you if there is something extra to be found. There are cheaper ways (Randy) of getting any of the other stuff done.
PS Does someone have the S4Rs tech manual, preferably as a PDF?
