The Armortek kits are impressive. Some years ago I was involved in terramechanics experiments. Using full size vehicles, in this case large tracked vehicles, would have been very expensive. Not only running the vehicles but finding enough land for the experiments. Altering the characteristics of the land would be difficult and expensive.
The answer was to by model vehicles, around the one sixth scale. We bought a couple of tracked vehicles, both expensive and unreliable. We spent more time repairing them than experimenting. On the occasions these models worked properly the experiments gave good results, good enough to try out on full size vehicles.
Unfortunately the unreliability was getting worse. I then saw an advertisement for Armortek, visited them, the result being that we bought what amounted to a tank chassis.
This was about 10 -12 years ago. The Armortek vehicle performed perfectly then and is still performing well now, I am told. It took everything we did with it without complaint. It ran on and through sand and clay, wet and dry, in just about every condition possible. Often (very) overloaded, carrying, pulling and pushing heavy loads.
The reliability, I think, was down to a well thought design and good quality manufacture.