There is a special tool needed(BMW part no:114180 ) for the flywheel bolts or grind down a long Torx T60 by yourself for it.
I do not use the flywheel lock tool for it to block the flywheel,but one of the bolts that hold the tranny in place and a screwdriver on the teeth for starter.
Tightening torque of the bolts:105NM
Remove the bolts that hold the cover in place and pull out cover with Sealing.
The sealing is quite easy to push out with hammer and screw driver.
To get the new sealing in,use a piece of wood and hammer it careful in.
Use a new gasket for the housing.
Tighten the M6 bolts with 10NM,the M8 bolts with 22NM.
If you've read the clutch DIYs, there's been a small debate about whether to change the rear main seal if it's not leaking. Some people changed it when it wasn't leaking and now it leaks. So, you may want to go back and read some of those posts and decide depending on your mileage.
No seal lasts forever, but in my case I decided not to change it when I did my clutch around 100K miles. It was not leaking, but the rear main on my 540 had leaked, so under normal circumstances I was inclined to do it. I also had the flywheel removal tool. I think what made me reconsider was that 1) some people changed it and it started leaking after the car was buttoned-up, and 2) if I recall correctly if you're not careful you can tear the upper oil pan gasket when you remove the rear main cover. To fix the later problem you have to drop the entire front axle to be able to get access to change the upper oil pan gasket.
I decided to leave well enough alone since it wasn't leaking. Obviously, if it's leaking then there's no decision. Change it.
You can buy the oil seal (7 below) on its own but for not much more $ you can get the complete cover with the seal installed (6). This comes with the gasket (8) and IIRC a set of capscrews (9) and (10) and new bonded sealing washers (11) for 10.
Watch you don't lose the two dowels (12) when you take the cover off. They are important for aligning the seal with the crank.