There are too many MorRyde IS systems on the road to assume that shocks will help the ride--it just doesn't need them. In fact, if you somehow manage to install shocks, it may serve to work against the fine suspension ride of the IS. Your call, if you really want to do that.
As to NevRLube bearings---have them on my '05 Suites (17400lbs) and pulled it over maybe 40k miles before having them replaced before going to AK in '12--none of the 4 bearings showed to be a problem waiting to happen--this was on 7k axles. In '14, I opted to replace the axles/brakes with complete Dexter 8k assemblies, including the NevRlubes. So, had maybe 40k miles on the original 7k axles/bearings; had possibly
25k miles on the new bearings when I opted for the 8k axles. Now at maybe 12k miles on the 8k axles/bearings and fixing to go back to AK in 2 weeks.
And, I sold the old axle/brake/bearing assemblies for $450.
I personally feel the NevRLubes are a fine bearing, but need to be checked for 'wobble' at some point after 2 years/30k miles. If you can't move the tire/wheel assembly vertically, then they are good. 100k miles is meaningless in RVs, but 5 years is sure a definite timeframe.
If I had had the money at the time, would have gone with IS and NevRLubes when I changed the axles, but that would have been about $4k more to replace everything.
'05 36TK3 Mobile Suites
'10 F450 new to me
'09 F450 Lariat 4x4--died