How much for 2.5 dual exhaust on a Duster

I just wanted to hear what others are or have paid for a set of dual exhaust for their A-body. I am plannining on going to the exhaust shop tomorrow so they can run 2.5 inch pipe from the headers with a X pipe all the way out the back. Muffler of choice/price is Jegs Force generic style flowmaster which I already have.
Anything to watch out for or suggestions would be great.