Since you want an identical one in terms of noise, I would think you should first figure out what kind the current one is.

If it's stock, then 6soda is correct; there should be lots of used exhausts available at a reasonable cost from owners who have gone aftermarket.

However, there is an advantage in buying a new stock one from a dealer and having them install it: It then comes with a lifetime warranty, including parts AND LABOR, so it's the last one you'll ever have to pay for. (Places like Meineke and CarX don't usually give you a lifetime warranty that covers labor as well as parts.) Just one more thing to consider in making a decision.