In all seriousness, knowing how an older Mercedes can eat you alive for maintenance costs, I recommend that people lease a new Mercedes, or trade them early. Sure, the cost of that path is high, but it is also predictable.
I’ve been through two spark plug changes on the the V-12s that included coils and plugs. Two coils firing 12 plugs each, and 24 genuine MB iridium plugs. MB plugs on some engines, not mine, but some, are indexed and aftermarket plugs cause problems. My cost, with a 20% discount on parts, and zero cost for labor, was $2,800. Retail on the spark plug change including labor these days is over $6,000.
That’s a spark plug change, mind you. A routine 60,000 mile service item. Not a major repair.
Lease it and avoid unpleasant surprises. Let Mercedes take the risk.