If you're thinking along similar lines, whatever your make and model, I'm here to say right now that we're both wrong. You won't have enough ground clearance. Your plastic-coated factory bumpers will be the rubbish you thought they might be, but hoped they wouldn't. I'm not having trouble (so far) with clearance at the diff heads, but with general body clearance. Careful observation has told me I'm about 50mm shy, and fortunately good suspension kits offering this sort of lift are plentiful. I'll probably go back to ARB, having had a good run with that company's kit on the Defender 90. For sure, even more air between me and the track might be nice, but 50 mils should lift me over the silly little snags I'm encountering.
Apart from being flimsy, the Wrangler's front bumper compromises the approach angle and the rear is a most stupid design into which the number plate holder is integrated. This holder sticks below the bumper proper and it's only going to take one or two more strikes to damage or even rip the thing off. ARB products and a liberal application of money will solve these problems, but they'll add weight and one of my aims was to keep extra weight low.
Oh well, my original plans seemed sound at the time. I'll report back as the project progresses.