Hey Don - Sorry for the delayed response.
Yes, I changed over from Super Steers to SE's air check valves.
Super Steers restricted air flow in both direction, while SE restricted air flow in only one direction.
It was and afterthought, as I had called to talk with SE about their Wax Valve Fan Control Module replacement. Was going over handling and ride comfort in general. And their thoughts were that I had three things working to impact our ride comfort on the front end:
1) 12R 22.5 Michelin XZE* set at a relatively high 110PSI
2) Road King Shocks - Their previous generation
3) Super Steer Motion Control Unit
All three working together, when hitting say a bump, or rumble strip, small hole, or the ALCAN - all restrict the ability of the suspension to 'cushion/absorb' the impacts.
On MCU's, their check valve restricts air not on the impact, but on the rebound. (My terminology, not theirs.
On the Road Kings, well, I like the handling. I could get the front re-valved, but I'm not going to do so unless the other steps do not make difference.
On the tires, well we lost two Michelin XZE*'s due sever pot hole edge impact. Put two BF Goodrich ST230's, still set at 110PSI for now (About to be lowered to 100 or 105PSI. Reference my post on updated four corner weights.) But, the ST230's have a less stiff tire sidewall (my terminology), and we both noted a difference in the front end ride just by the ST230's vs XZE*'s).
So, decided to have the SE check valves added to the front, to help on the ride comfort. And while doing so, went ahead and did the rears too
And yes, we both noticed another notch in improvement of road imperfections.
Handling has remained the same, with the tires and the check valves added. I'd estimate about a 15-20% less stiff/harsh front end ride, by these changes so far. Will be dropping the tire PSI before heading out, and expect it will help a bit more.
And another yes, I did impact our ride by my choices of XZE*'s, Road Kings and Super Steer MCU's. But I value handling over comfort, and will do all that I can to retain the improved handling. And of course, this is all with my years chassis IFS.
So Don, knowing you, suspect none of the above were your questions about SE MCU's
But, I wanted to explain where we were, and what changes we made, and why.