Once you pick a side to work on, and you get the center 10 mm socket head capscrew out, I found it was much easier to lift the engine by jacking it up so the little drip shield made of galvanized sheet metal on the top could be rotated out of position. On my car the shield hindered access to the inboard socket head capscrew that holds the mount to the subframe structure.
I would recommend you not unscrew both sides at once as the reassembly can be more complicated if you are trying to align bolt holes for six bolts at the same time. I found by doing one side and then the other the bolt insertion was pretty straight forward. I also only loosened the fasteners on the "idle" side as I was a little concerned with how far I was lifting and tilting the engine that I might bend the center fastener.
In the end, only the center fastener on the passenger side (the second side for me) gave me any trouble. I had to loosen/remove the two smaller socket head capscrews on the sides and jack the engine into postion about three times to get the center fastener in without cross threading it. The motor mount strut with the tapped hole you are going into looks like aluminum to me, so you have to be careful to avoid cross threading. A bright, pencil beam flashlight to look into the alignment as you position the engine above the mount slightly was also a help. Don't forget the galvanized sheet metal shields when you put it back together. They have a little ">" mark to point forward to help get them in correctly. I just put them back in by positioning them so they made access to the capscrews that go in from the top as hard as possible, and noticed the arrow mark was pointing forward.
Good Luck, Jim
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)