I had a crappy seat in my first rv (Allegro). I bought a Bostrom Wide Ride and love it. I put the crappy seat back in the Allegro when I sold it and put the Bostrom in my current rig. It's got two air lumbar bladders controlled individually. I love it.
'03 Freightliner FL112, 295" wheel base, with '03 United Specialties 26' living quarters, single screw, Cat C12 430 h/p 1650 torque, Eaton 10speed , 3.42 rear axle ratio