Tbh, changing air bags is not a common thing to do.
I have heard of a few people doing it on D3s for the exact reasons the poster described, prolonged driving over ******te roads wearing them out.
Most were from Aus though from long extended outback driving over awful terrain.
Don't be put off by stories of large bills.
It's an accepted way that large car's will give large bills. My mates questioned how i had spent so much on mine till i showed them how a front lower arm for his car was £22.50 off ebay and mine was £115. For the same part, just one was 4x the size of the other...
I'm a fussy owner when it comes to cars and having been burnt by fitting pattern parts on an previous car, with the issues they threw up. I wasn't making that mistake with this LR3. It get's genuine parts which does cost, but i know they will fit and last.
The car has failed me once in 27k and almost 2 years of ownership, due to a starter motor dying. Hardly the end of the world and £170 later i had a genuine LR replacement in place.
I've changed all 8 wishbones, 4 drop links, 4 arb bushes, the rear hub bushes and the brake lines and upgraded the full brake system.
It stops and handles like a new car, and rides far better than any of my LR3 driving mates cars.
A large hit like the poster and myself is sting the wallet, but i have nothing on the suspension that is older than 1 year and 15k, so will cover 80k at least before needing any work done again.
Out of interest, we in the uk are rather spoilt for choice for indy's to use, and also for parts makers to choice from.
How is the supply for the newer models in the US? Do you have a decent supply network or is it really just main dealer supplying parts?