I have a 1981 MB 300SD and I was wondering about an engine block heater, (some kind of wall socket plug-in unit to warm the engine prior to starting). Our regular mechanic said they couldn't find one and there wasn't a good way to add one. First of all, besides being beneficial for passengers (my wife!) I assume it would be good for the engine, especially on those cold Wisconsin winter days. But rather than make a wrong assumption I'll ask, is it really beneficial and if so, are there units or companies people recommend that have a good poroduct? Thanks! --Peter