How much labor are they charging? That seems an awefully high estimate based on the amount of time to install it. I work at a dealer and I know for a fact that couner sale parts are warranted for one year unlimited milage, wear items excluded, just like if they installed it. It's a very easy part to change, all you need is a good set of hands and the right tools. Dexterity is more important than tools though because of it's location. I think so many of them fail is due to their close proximity to the exhaust manifold.