Thats the BMW derv lump, so us "L" Series ZS lot may not know too much, might be worth a quick look at, 75 & ZT Forum, and see if you can pick up some tips.
With me its just service history, belts, normal stuff. Suppose the clutch needs checking, had my one done ZS, at 75,000 odd. The dervs do push out a fair bit of torque. Tyres are another thing to look out for.
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