I made the switch from Koni to Road King just before we left on the current trip. The price was $1400 and change direct from Road King. I was extremely impressed with their fast two day shipping to San Diego. We've only traveled 600 miles so far and there is a noticeable improvement in the ride. The porpoising has been completely eliminated and the side-to-side sway is vastly improved. However, I will say that the Road Kings seem to provide a bit stiffer ride. This stiffness may be more noticeable, and possibly objectionable, when traveling on our wonderful California roads. That may be something we’ll just have to put up with while we escape to other more road-friendly states.
As per Road King, these are the model numbers they recommend for an Alpine Coach:
“The front axle shocks are # 5-A 3/4" X 1 3/4" spacers. The rear axle shocks are # 4-A 3/4" X 1 3/4" spacers.”
2006 Alpine 36' FDTS