Well, I've replaced the clutch in my 740 B230E non turbo with the help of a friend and an airbag to lift it. No way would I consider taking out the engine. Just unbolt the driveshaft and driveshaft bearing holder fron the car, if you split the driveshaft, remember to mark the way it came off, then unbolt the gearbox from the engine. The rear engine mount is on the gearbox, so you have to support the rear of the engine too, I used a bottle jack for that. You do not have to remove the engine. The hardest bit is separating the gearstick from the gearbox and don't forget any wiring to the gearbox that needs to be disconnected, eg overdive and reverse. Just don't try to lift the gearbox on your own unless you are the Hulk.
This is on a non turbo and non auto, for those who are wondering.
I did this on a M46 with overdrive, but the same applies to a M47 gearbox.
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'86 740 GLT 2.3 injection 7 seater estate, '89 740 SE 2.0 injection saloon, '87 BMW 316 carb Coupe