Not an expert here, but I think one of the problems with 4wd is weight. Mostly they go overweigthed. I think a standard 4wd, a real one or a pick up, can do it with minimum preparation. Protections and suspensions. Of course, it depends on your goals. The faster you go, the more you will brake.
In Mauritania we met a local, good friend of a few members of the spanish team. He has a Toyota pick up. He overtook all racing cars in a beach section. While all the others were jumping around, he was driving smoothly throug the sand. His car is standard and he is very experienced.
Track is standard Morocco. Lots of sand in the south and in Mauritania. Senegal, the same. Lots of stones in northern Morocco. Adapt your speed to the conditions and will be fine.
Again, not an expert.