Well we have a rear kitchen refer on back wall. We did have one issues last month, we were going to Ft. Stevens SP heading north on 101 south of Seaside. The standard "Rough Road" sign that has been in the section that floods every year. Well it was MUCH rougher than in the past. Truck with new Bilstien's did OK, :) 5er with no shocks(yet):S, I swear left the road! Rough spot was more like a speed bump, speed was 45.
When we got to the campground we found that the beer and soda in the refer door shelf's had broken all three shelf's! I am not sure if it would have been better with a center kitchen or not. We have the rear kitchen as DW loves to cook on the road, and this is a good size kitchen to allow that.
I see that as an extreme case, no other issues. :)
Next expenditure on the 5er is shock kits for both axles!!!