I had a powered reclining loveseat installed in our 31FS a couple weeks ago. We were driving through Indiana, so I paid a visit to Lambright Comfort Seating near Middlebury. They had a model in the showroom with color/features I liked. They were able to install it on the spot.
I removed the jackknife sofa in their parking lot. It took me about 15 minutes. The base of the jackknife was secured to the slide room floor with four L brackets and nuts. The threaded studs coming up through the floor were not removable and stayed in place. The right and left arm assemblies were secured to the jackknife frame with a few wood screws.
After disassembly, I had 3 pieces that would easily pass through the door. Rather than disposing of the jackknife in Indiana, I laid it flat on the cabover bunk and brought it home. It's now stored away for future use/resale.
Additionally, I removed the two vertical valance sections from the window behind the sofa. Pulled out two screws and a few staples. They may not have interfered and likely could be reinstalled.
As stated, the existing seat belts work fine when passed between the seat and back cushions on the reclining loveseat. When fully reclined, the female side of the seatbelt tends to "disappear" behind the cushions and has to be fished out again. I have longer seatbelts to install in those positions.
The framework for the new loveseat wasn't an exact match for the old mounting pattern, so they secured it to the slide room floor with lag bolts. I will likely add some additional brackets for more security.
I took on this upgrade without my wife present - fortunately she was happy with my choice
My kids were there to help pick it out and they LOVE their new seats.
-Doug