It was replaced with the "Y" pipe in place.......we had to wait for the catalytic converter to cool down.......and you are hugging it.
The mechanic removed the big flex hose that goes from the throttle body to the air cleaner.....below that is a joint in the speedometer cable.......and he disconnected that.
You should be able to do the job with the front wheels up on ramps......but.....like I mentioned....he told me that he was going "by feel" as he could not see the bolt that he was working with.
He did mention that some vehicles requre the "Y" pipe to be removed.....then went under mine, and felt around and told me that we were lucky.
He had his lifts occupied with other vehicles......so he just jacked up the front.....laid on his back on the floor and did the repair.
In a pinch, you could have a local shop do the job also.