I have 5 star on my 2012 V-10 class A. I also had it on my 02 V-10 Excursion. Made a huge improvement in both. The shifting alone was well worth the investment! I gained .5 mpg on my Excursion and .3 on my MH. I mainly got the tuner for the MH to do away with the horribly intrusive drive by wire that would pull throttle on you when you needed it the most. 5 star still leaves some “safety” in there but it’s far better. And the shifting is much improved! You do get some extra HP but it’s not much and really isn’t needed once the drive by wire is taken care of.
Just about every MH should be run in Tow/Haul. The reason is the chassis is always loaded. I really wish they would make it so the T/H default was on instead of off. Might be good for an empty bread truck or cargo van, but not on an always loaded RV.