If its an educated decision, it might make sense. But even that depends on the severity of the problems & the availability of the replacement engine. It sounds more like you're frustrated. If it were my car, I would figure out exactly what's wrong, how much $$ to fix, and how long the repairs will take. It will probably be cheaper to rent a car as suggested while fixing the repairs. It depends on your own circumstances and your mechanical abilities and collection of tools. Old VW's were air cooled & held in by 4 bolts. I'm told guys could pull the motor in about 20 minutes. Not so easy with a Mercedes.

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Brian Toscano