Yeah if you actually hit a rock on one of the stock skids, you'll see how thin it is. Look for some beefy 3/16" to 1/4" thick skids. I'll be making some pretty soon.

As for sliders, they're a great investment! Protect the rockers/doors offroad, and also help fend off carelessly swung car doors and shopping carts at the mall. I make sliders as well, could probably hook you up with a bit of a deal on a set of returned sliders coming back to my shop in the next week or two(nothing wrong with them, just sent the wrong set to a customer in Hawaii on accident).
An aftermarket should not affect air bag depoloyment, they're inertia sensors like max said. You can find them under the hood on the inner fenderwell under the battery on the driver side, and under the air intake on the passenger side.