I put our new Koni's on this past Friday. It only took about 20 minutes or so per axle. When we took it out for a short spin, the improvement was noticable.
The side to side sway was drastically reduced and the rebound over bumps, cracks and expansion joints was also much better. I still think I need to add the Motion Control units to help with crossed-up transitions such as driveways and I think a steering stabilizer is also in our future to help deal with cross winds but The FSD's definately helped.
The coach is more comfortable and less jarring so these were a great improvement overall.