wouldn't expect it to be that expensive for the cl9 though.

had a quick look at the service guide.
you can save a bit of money by:
buying aftermarket pollen filter so they don't slog you.
bringing your own oil.

and, I think they change air filter as well, so if you have an aftermarket intake or a k&n you won't need that.

otherwise it's just brake fluid change and oil filter change as well as all the normal checks.