Welcome, and congrats on a nice car.
You only need stronger springs if you expect to carry very heavy loads.
If this only happens occasionally, consider air helper springs, especially on the rear. These can level you when heavily loaded, but don't have much impact on the ride quality when empty.
Only if you carry heavy loads all the time (steel bumpers, fridge, drawer system, winch, double spare wheels etc) or do rock-crawling do you need stronger springs.
Having said this, a top-notch set of shocks might make a huge difference. But expect to pay more than the quoted figure above. I am talking about brands like Fox or Radflo.
Just one more thing: in sand, weight is the enemy. So, for this challenge, keep it light as possible.
Mag ons ons kenniskry met lekkerkry aanhoukry.