Certain vehicles ( examples : Jeep Wrangler , hammer , Nissan Xterra , G wagon ... etc ) were produced in the first place for military purposes in their stock form. However when they were shifted to the public the stock form has been modified slightly to accommodate the civilian needs in terms of appearance and compactness . However the core remains the same like engine and drivetrain chain. That’s why we see these vehicles perform excellent in their stock forms even to the extremes of the different environment with minimal needed no major modifications ( example : bash plates , kill switch’s , tyre size to certain extent ) , ( major modification. In my opinion is a modification that entails replacement or compensating an entire system e.g : huge tyres needs lift more than 2.5 in goes with that spacers then re gearing . Possibly the entire steering system and later ... etc ) ... for all these reasons and also reasons that I am using my vehicle on the road , I believe that the majorly modified vehicles should be reserved for very specific controlled recreational event in specific area and driven by specifically trained ppl.
I think our common offroad vehicles in their major stock forms can perform reasonably with no major issues.