I realize this, my first post here, is not exactly on-point, but I think others, beside myself, would like to know what problem(s) you were solving by the suspension additions you made to your 2008 Sprinter chassis. BTW, I have owned RVs- all except one motor homes- since 1974, and have problems with both, more extensive in some new at some times, and with others more extensive with used!
I've moved your post to the appropriate forum (Class B Motorhomes Forum). It's always best to not post on other peoples threads with a totally new topic. You'll get the hang of it, AND Welcome!
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad