We ordered a swivel seat base from Shop4Seats and really enjoy using it. It has not been difficult to swivel just have to move the seat forward and then backward as you swivel. Its a little tight against the passenger door when swiveled 180 degrees, so we normally just swivel about 120 degrees.
Installation was interesting. The standard bolts from the old base were not long enough. So I removed the carpet under the seat base (real pain in the ##@@$). Clean the glue and found there were a couple of items protruding from the floor. I drilled holes in the seat base so it would fit over the items and it bolted down with no problem.
Think you would enjoy the extra seating.