FWIW, I have some extensive experience in this area. At least as it applies for Ford motors.
Best case scenario, you gain some power and have no issues.
Worse case scenario, you get busted by DOT, your truck gets impounded and you get to pay some serious fines.
Now your not likely to garner the attention of a knowledgeable patrolman in a motorhome but you do need to be aware of they path your going down should you choose to do these mods.
I've got some real life hands on experience with both situations. As they say, you have to pay to play.
Im not going to debate the ethical side as I believe government has gotten to big for it's own good and certain agencies have much more power and scope than was ever intended.... but thats just my opinion and many people believe we need to be protected from ourselves.
2009 F350 CC LB 4WD
2017 Jayco 355MBQS