Life time warranty is only for USA market, only 1 year warranty for overseas market.

Which fuses do you remove for doing this job?

Just open right side pannel in your trunk, the subwoofer side, then you will find the fuse box inside, the 30a fuse that is the most front one. You can find the description on the back of the pannel saying which fuse for which function.

BMW New Zealand quoted me $300 EACH for the air springs, with a 10-14 day delivery time.

That is what the dealer quotes to me here in Hong Kong. You may try some independent car parts dealer who also carries out BMW parts business. They will be definitely cheap, half price for the exact same OEM parts. Here in Hong Kong, there are lots of independent car parts dealer who sells OEM BMW parts at very cheap price. For example, for front air spring struts, US$540 each side; rear air sping, US$160 each side. Some OEM product for suspension like Lemfoeder control arms are also sold at a very low price, much cheaper than some online shop on the internet. Of course, those parts from indepedent dealers have no warranty.

Thanks for the write up OP. I just replaced my rear right air spring last night after it started to sag a few weeks ago. I have a 2001 4.4 Sport model so I ordered Arnott part A-2503 which replaces BMW part # 37126750356. Total for the part was $113.51. I ordered on 7/20 and received the part on 7/23. I did the install by myself last night in about 60 minutes.

I had my left rear spring fail about 2 years ago and at the time was too busy to DIY so I ended up having a local independent shop replace the spring. Total then was $510 and included 3 hours of labor at $99/hr. After doing the second spring myself last night I feel like I was ripped off on the labor. No way this takes a mechanic close to three hours when I did it myself (for the first time) in about 60 minutes. I am glad I saved $400 this time around though. :D

Good Job....

My vehicle is 2001 BMW X5 4.4i Sports. Do I need comfort air spring or sport air spring? I see yours is also sportpac but you ordered comfort version of the air spring. Let me know Thanks.

My vehicle is 2001 BMW X5 4.4i Sports. Do I need comfort air spring or Sport air spring? Thanks.

Their website says about the sport springs:

Besides Sport Suspension the BMW X5 Sport Package consisted of black exterior trim and, for the 4.4i, 19-inch tires. Vehicles equipped with the the Sport Suspension from the factory have firmer, shorter springs that result in a lowered vehicle stance, along with shock absorbers that have been valved to yield firmer dampening.

Based on that I would think you want the Sport.