The 530/540i was rarely sold with manual gearboxes, (and the 740i was never sold as a manual in the UK). So there's a bit of expenditure (or fiddle) involved to get a clutch and flywheel. As with the gearbox - finding a manual donor car to start with is probably the best option as it gives you everything you need.
I made up a lightweight manual flywheel up by welding and bolting a new plate to the automatic flywheel, machining the face, then drilling and tapping it to accept a Ford V6/Cosworth 240mm pattern clutch bolts and dowels. After driving the car for some time with vibration i got around to taking the flywheel out again and sent it off to have it professionally balanced. It weighs around 6kg which is really too light for smooth running at low idle speeds.
The original manual cars came with dual mass flywheels (DMF). The purpose of the DMF is to isolate the crank from the mass of the clutch and outer flywheel slighty to lower the vibrations and rocking that otherwise comes from the high compression ratios used on modern engines. But they are heavy and the cushion between the two does wear out. Some mechanics advise changing the DMF at the same time as the clutch is renewed.
VacMotorsports and JBracing both sell lightweight single-mass race flywheels and clutches for the M60 & M62 V8s and they aren't that much more expensive than the new DMFs.
Here's the DMF used on all manual 530/540i cars :
