Yes, you have a very valid concern.
I damaged, simply driving in the City Of Los Angeles, two sets of black valves, plumbing, etc.
In fact, tomorrow I get my truck back from Mike Thompson RV in Santa Fe Springs, CA after their repair of my lower fiberglass which initially was quoted at over $13,500 (AAA are paying for that, less my deductible).
These units are way too low, and at the lowest point, the black water and grey water valves sit, and an inch above, $13,500 worth of fiberglass repair (AAA went in and got it reduced to under $9000 but)
And it is detailed here;
http://classbforum.com/phpBB2/viewtopic.php?f=12&t=1616&start=252
I was one of the owners with this problem until I found the absolute Guru of Suspension mods, BILL ERB of VALLEY SPRING WORKS in DIXON, CA.
340 Industrial Way Ste G
Dixon, CA 95620
(707) 678-3944
Here is my Yelp Entry below the first entry for an Alignment shop you will need to visit after the Lift;
http://www.yelp.com/user_details?userid=MkgIduK6ArsHwmcvJEuZtw
And if you don't do this, and intend to drive your Class B beyond the freeway & easy city streets, be careful and make sure you have excellent insurance.
But the best insurance is seeing Bill ...