I dont think it will make any difference at all to vibration, since the fan and clutch are neutrally balanced.

However, it will probably increase your mileage a tiny bit, reduce engine noise a tiny bit, reduce the load on your waterpump bearing, at the expense of less reliability, less potential cooling (unless you buy a REALLY big electric fan, which would probably require an alternator upgrade), and perhaps a bit more expense.

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1991 W124 250D - 130k Miles