Took me about 4 hours but I didnt run into too much trouble so it went quick.
I would replace the VANOS oil line and washers while you have the oil filter housing out. And make sure you remember how the hoses are arranged before you take them apart..specifically the VANOS oil line hose and the hose that connects to the front of the valve cover from the oil separator.
Feel free to PM any questions if you get stuck anywhere. I'll do my best to help you out.
BMW 323I 5 Speed