Many people quickly realize you don't want to replace tinfoil springs more than once, so if they're unlucky enough to replace them on their own nickel they go with Old Man Emu springs or other alternates.
Take a look at the Discoweb, there's a tech section that's loaded with good info.
Hanging out with my service guys at LR (which I get to do quite often , we got on the subject of Range Rover repairs one day.
They were mentioning that if you dent a rim that it costs $600 to replace the rim.
One oxygen sensor for your exhaust is $200, one catalytic converter is around $1800, the complete exhaust assembly (minus catalytic) would be somewhere between $500-700. So, replace the entire exhaust system (plus labor) and you're looking at around $2700-2800.
Not sure what air suspension costs to get fixed, but I would think that it isn't cheap.
I personally would pay the $2700 for the extended warranty. If you never use it, consider yourself fortunate! If you need to use it, you'll be glad you have it - kinda like homeowners insurance.
I was on another mailing list for Disco's and a lot of the guys there were buying 3rd party warranties for their Discos - goto www.msn.com and search for: auto warranty --- you'll get quite a few hits. In some cases, these can be half of the dealer's warranty, and some have a deductible (like the first $50-200 of a repair), which may make great sense.
I put in a 98 Range Rover, 32,000 miles, with manufacturer's warranty still left on the vehicle and I received the following from http://www.auto-extended-car-warranty.com/:
5 Years 75000 miles $2195
So, if you're not opposed to paying a deductible and waiting 30-60 days for reimbursement, an aftermarket warranty may be a good option.
Thanks - wasko