Just as an aside to everyone saying that the hi-lift cannot be used on the JK, that only applies to non Rubicon models.
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The jack can definitely be used on the Rubicon rock sliders with no ill effects, as I have done so many times. As for storage, I keep mine in the Rugged Ridge mount on the back of my tail gate. This mount is not ideal, as it does not mount flush to the tail gate, but has two spacers, creating some weak points in the attachment. My kit also came with the incorrect bolting hardware, and the spacers did not fit properly under the latch covers, causing them to eventually crack.
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An interior mounting point wouldn't work for me, as pretty much every time I have a need to use the hi-lift it gets covered in crap that I don't want in the Jeep or all over my other packed items. With the Jeep loaded it would also be more difficult to get to/replace every time. I definitely think the rear of the vehicle is the best place to mount it, I just wouldn't recommend my particular method.