I run the sami case in my LJ hard mounted with a 3rd plate around the rear output, and have never had any problems running 34s with a 2.3. But it's offroad only.
When I got the sami, I ran both hard mounts and rubber mounts, and preferred the rubber mounts for on road, and the hard mounts for offroad. Throw a locker in the rear, and you had to drive it "just right" with the hard mounts on the road. One thing I did do with the hard mounts, was to add a chunk of rubber between the t-case cradle and the aluminum mounts. I actually used the body spacers from a sami. :redneck: But a thick mudflap would accomplish the same thing. This gave it a little cushion, and a little isolation from gear noise. I did end up swapping back to stock rubbers when I used it more onroad.
There's a guy down in yelm that runs stock mounts, but he cuts the studs off both sides, then through-drills them, and runs a bolt all the way through like the aluminum mounts. If I'd have kept the sami, I'd probably go this route.