If it'* the air struts that have blown the air bag inside, and can't inflate/lift the rear end of the car up anymore, your best bet is stock replacements. Will it happen again over time? Of course, but we're talking another 10 - 15 years or so, just as it took that long for the originals to finally go out. Plus that'* one of the coolest features on the car (no *** dragging effect, even with a lot of people in your car/stuff in your trunk). Is your air compressor working?
If it'* the springs, same thing. Replace them with stock, or OEM quality springs, and you should be good to go again for a long time. No matter what you replace them with (aftermarket/performance parts - which I don't think they have for these cars), the same thing is going to happen over time. There'* no such thing as an indestructible suspension part. At best, it might last you a year or two longer.