No special tools as such... That special tool for removing the bolts under the camshaft can be substituted for an 8mm ball headed hex driver.
The cam sprockets only fit one way. They are on a keyway.
The only other thing you will need is something to pull the pins holding the inner chain rails. I put a short m6 bolt in the pins, with a penny washer, and used the claw end of a claw hammer to lever them out. I used a rag between the hammer and cyl head to stop it marring.
You'll probably need to helicoil the head bolt openings after you've pulled the heads. Some of threads in my bolt openings just crumbled away.

__________________
Ben

'85 500 SEL
'85 928S2
'88 560 SEC
'90 750i