At 100k, these cars don't show much wear unless abused. The interior and exterior should be very clean. However, if the car is from an area with salted winter roads, it will show (rusty underbody, and possibly sheet metal). Mechanically, the transmissions are long lived if maintained (30k fluid changes). The engines can use oil (valve stems, front seal), but these are fixable and hard to identify with inspection. Otherwise they're good for many miles (mine was sold with nearly 250k miles and it was running strong. The AC evaporator is a weak point and replacement requires dash removal. It's good that it was just converted to 134a, but I would look closely at those records.

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07 E350 4Matic wagon, 06 S430 4Matic, 99 SLK 230
retired W210 (x3), W124, W126