Both cars have more or less the same problems. The problems are wide ranging and they don't all happen in one car. You have some people who have experienced certain issues and others who haven't.
Headgaskette failure usually precipitated by a pronounced oil leak at the rear of the engine head.
Timing chain cover gaskette failure.
Hot start problems (numerous causes).
Cold start problems (numerous causes).
EHA gas leak.
Fuel pump(s) failure.
Fuel pump relay failure.
OVP (overload voltage protection) relay failure.
Transmission rubber coupling wear.
Rear "Thrust" link suspension wear precipitated by rear skip when hitting a bump during cornering.
Rear subframe mounts (wear) sometimes precipitated by floaty ride and crosswind instability.
Blower motor failure for climate control.
Heater valve failure.
Ignition tumbler failure.
Engine Mount failure precipitated by persistant frame vibration sometimes mistaken for rough idle.
230E has a fan switch that can fail to turn on the fan at the correct temperature.
Water pump failure precipitated by coolant leak around water pump seal which promptly evaporates and sends owner on wild goose chase.
Idle valve failure.
Throttle actuator failure.

I refuse to think of anymore because its making me depressed but needless to say there is no substitute for having all the cars records at your disposal and having a trusted tech who really KNOWS these cars take a look at the car away from the prying eyes of the seller
Hope some of this helps.....