I have always had muffler shop do this, using mufflers that I supplied. One issue is that the Center Resonator and the rear muffler came from the factory as one piece. So, if it has never been replaced, it will have to be cut. The chain store muffler places wouldn't touch it, so I found a little muffler shop. They did it cheap, as in 60 bucks.

Next issue is that the fore to aft location of the new muffler is critical and spelled out in the factory manual.

Steve