Certainly, weld-on sliders done properly are going to be stronger. But I really don't "need" serious protection. This is for light, occasional use at best. I use my 4Runner more for camping and hiking trails than anything else (well, theoretically... it spends more time in the garage than it should) and I like the idea of being able to go back to stock.
So are there no "zero mod" bolt-on sliders on the market? I don't want to drill the frame unless I absolutely have to.
What you are looking for are called tube steps. Not sliders.