If you're going for a bolt-on set, look for brands that use a heavy plated U-shaped channel that bolts around the frame as this tends to be as strong as the welded units. (Such as my CBI ones, I have heard that Demello & SW do the same.)
Does the armor thread discuss in regard to the bolt-ons that have the u-shapped channel for bolting to the frame?
My shrockworks sliders are great! BUT depending on how much you'll use them offroad, if I had known more I would have gotten kickouts and looked for ones that stick out a bit more for use as a step.
There are more choices now than ever so really do your research. Mine are bolt on and they are not going anywhere!
There are TONS of options. I'm going to weld a set on mine, but there are some decent bolt-on options.
Start your research here... 4th Gen Armor Thread - Toyota 4Runner Forum
By the way, I've always liked the HD-SKO sliders from Stubbs Welding... check 'em out.
I'm not entirely sure if it was detailed in the armored thread. But I have a set of bolt ons with this design and its been as strong as the frame itself. I regularly just kick the pads on my lifts on the sliders and lift the car off them and they have taken a beating off-road well also without twisting, or what not.
BlackWorks, are yours the SW sliders?
I believe domestic manufacturers void your warranty if any welding is done with the frame? Using the proper grade bolts allows for easy replacement also.
That's not the case. Because of the Magnuson–Moss Warranty Act they can't deny a warranty claim unless they can prove that the modifications you made directly caused the problem. So, if the welding is actually the cause of whatever goes wrong they won't cover it. If there has been welding but it wasn't the direct cause of the problem they can't use that as a reason to deny the warranty claim.