You could go to the rental shop and pickup the welder, go home, raise the car, wrestle with getting the old exhaust apart, install the new one, weld the mufflers in place, spit out the grit that landed in your mouth, lower the car, return the welder, pay the rental fee....
...or...
...take the mufflers to a local shop and pay them $30-$40 and drive away a short while later with the job done.
Guess you can tell which road I chose.