$450 is pretty standard and reasonable considering what they have to do just to get to the oil pump. the whole timing belt assembly has to come out- cover, seals AND the belt too- b/c it is all located right behind there. They also usually replace your timing belt since the old one will generally be oil soaked which is where you get to $450 instead of $380 or so- the belt is a $60 part but you shouldn't use the old one since they're already in there and chances are you'll need the job done again once the belt goes out then you just coughed up almost a grand for the same job twice!! Screw that....