I don't know if these are "benefits" (you didn't define what you are trying to gain). The heavier torsion bars will be stronger and less likely to break (though I don't know that the torsion bar is the "weak link" in the front suspension). I would expect them to be "stiffer" in terms of ride and handling (some people like stiffer some don't).
Randomly replacing the bars without a specific goal offers little benefit. If you are trying to raise the vehicle, there are better ways to do that. You run the risk of uneven tire wear and stressing the tie rod ends.
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