They bolt to the 2 large body-mount bolts and the underside of the sill via 8(?) smaller bolts.
My truck is a bit far away for a visit as I'm up in Walnut Grove, though I have it in the bay at least once a month for something. You are welcome to come have a look sometime if you are in the area, but DavidW might be a better bet or you if you're in the bay often as he's on the peninsula. I suspect he'll be at our gathering on Thursday. I'll be there, but I won't be driving the Rover (work van for me I'm afraid)
My sliders and skids have been well-used this year. Saved my driver's door from what I thought was a sure-fire dent last month when gravity got the better of my line on a loose down-hill.
Those sliders look really great. I am new to the world of Land Rovers and just got an LR4 earlier in the summer. I had the pleasure of meeting Pedram when I went to a club event with Mike (astateofmike). So the used LR4 that I got has the LR running boards, which lower the ground clearance by about 1 - 1.5". I want to pull them off and put on some sort of slider and was comparing these sliders with the ones from Voyager Racks. I am in Livermore, would it be possible to swing by some time and see how they are installed? Also, are these bolted to the sill or to the body?
Welcome! I have a 2013 LR4 (see my signature below) and have the same Tactical 4x4 sliders and skid plates (transfer case and fuel tank) as Don, as well as the front ARB bumper. We also have the same Urban Offroad roof rack, though mine is standard and he has the low profile edition. I am working on the rear bumper ideas, but Don's is awesome!
I actually had a 2011 LR4 before I traded it in for my 2013 (ordered exactly what I wanted) and had both Voyager and Urban Offroad rock sliders and I will say that they are nice, but are only sill guards. You do not have much protection for your air compressor or air tank, and under body. I had the Urban Offroad on my 2013 (got a deal when I got my rack), but I switched to the Tactical 4x4 for better protection, which they certainly offer. You really can't beat the sliders for protection and, as Don says above, he has the scars to prove it. If you get the Tactical 4x4 sliders and have a 2012+ model LR4, then you do need to relocate the air compressor with a supplied bracket so the slider will fit. Sometime in the 2012 model year they changed the air compressor on the LR4 from a Hitachi to an AMK. The latter is a better compressor, but it hangs quite a bit lower than the Hitachi.
If you do plan to do any off roading, I would remove the OEM running boards, as they will likely get damaged pretty easily. If you did not want to go the Tactical 4x4 route (they are VERY heavy and definitely affect MPGs and ride), then I recommend the Urban Offroad sliders, as I had the Voyager and had some problems with the powder coat coming off and the hardware they sent was terrible. I know a few other guys from the LR4 forums who have been complaining. Derek from Urban Offroad is in Southern CA and makes a good product. If you drive down to Temecula, he does free installs (though they are very easy). The Voyager and Urban Offroad sliders offer about the same protection, though I think the Urban Offroad sliders are made a lot nicer.
I am in San Carlos (mid-peninsula), so kind of far from Livermore, but if you are in the peninsula I am always happy to show you my truck. I will be at the peninsula gathering coming up and at the Annual, though only for the day.
Feel free to send me a message with any questions - Don is also an excellent resource.
2013 LR4 (Discovery 4)
Full-sized Baja roof rack, ladder, front skid plate, tail lamp guards, 18" Compomotive PD1880 wheels with 265/65R18 BF Goodrich A/T KO2 tires, Tactical 4x4 rock sliders with steps, gas tank and transfer case skid plates, ARB front bumper with WARN XD9000 winch, RIGID Dually off-road lights, Kaymar rear bumper with custom tire swing-away, and a bunch of other stuff.