I replaced the scissor jacks on my X19H and gotta say, didn't notice a difference even though the weight capacity per jack was far higher with the new ones. I thought perhaps the higher weight rating would remove play in the jack and make things more stable, but nope. Basically the same.
Biggest upgrade for stability I experienced was going to a stable step set of stairs.
Everything else - different leveling jacks and x-chocks provided very minor changes.