In retrospect, you "might" try this routine with the add-on's, esp. now that you've revealed where you've been driving up on I-90. Personally, I
would start with the SUMO's and NOT ADD any of the other stuff until you
see just how the SuperSprings work. They do tend to CUSHION the ride as the are in direct and constant contact between the axle's and the former
bump-stop holders...in fact they fill the gap where the former left a gap and only came into play when you really bottom out. Sumo's tho, are full-time
working and in unison!
The next step might be the upgraded shocks and see how that works
with the SuperSprings(SUMO's). That "might" be all you need at that point...dunno...tho. a sway bar on the rear axle(at least) will really defeat a lot of the rock-and-roll effects. I guess what I'm trying to say is don't get TOO overzealous in your plan to unrattle your teeth? You just might
stiffen things up so bad that you will magnify every little crack and bump
and it could work against you? Gotta find that sweet spot for YOUR particular unit...they are ALL different and have different rides. Can't rely
on what everyone advises about what they like as they all have different
chassis and suspensions(and weight loads) going. Consider that!! We know what you are trying to accomplish but please consider what I just said...LESS is MORE!? My Sprinter 3500 Solera has a very cush ride and
am happy just with the SUMO add-on's and the hefty sway bar on the back...both at speed on the highway and the backroads. Have test driven
other Chassis models before I purchased my Mercedes Sprinter with the diesel and am happy we stumbled into that. The others(v-10's, Thors, etc., et al, tho nice units were pretty unforgiving on the road...).
GOOD LUCK to you in your quest...git 'er done!