I agree with winmutt now that I've got a wagon.
SLS is an amazing system, with the common wear components being no more expensive than shocks in the long run (accumulators, high pressure line and height adjust valve).
The shocks and pump, the most expensive parts, rarely fail, unless abused and run dry. The problem you'll encounter often is: it's a set and go system, and previous owners have never replaced a thing, letting you have all the fun and expense of repair. I was lucky enough to get one with a fully rebuilt rear suspension (hydraulic struts included).

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