8mm allen on the bottom, 17mm socket for the top. 10mm, iirc, to hold the heat shield on the exhaust side. The tranny mount will hold the engine 'in place' when you jack it up, so the new mounts should align pretty well...I've had best luck just starting the top bolts first, lowering until there's barely pressure on the cross member, then fitting the bottom bolts.

One thing you might want to do is spray around a little with some simple green and then rinse with a pressure nozzle...it gets pretty greasy down there!

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1973 280 - Current Project Car
1979 240d - 100% Stock
1982 380sl - 100% Stock
1985 190e 2.3 - Heavily Modified