That depends on the dealer, and their labor rates. I would not expect it to be more than a 2 hour job, though I could be wrong. I have seen labor rates between $20/hr and $80/hr.... but then again, changing my plugs (which I supplied) cost me like $190 for the labor.
If the part is $200, I would not expect to pay more than $500 at the most, I would be happy with under $400 though. That is if you are not willing to attempt doing it yourself.