I found this on the American z4 forum and I think it will be useful to quite a few guys on here as it literally has tons of very helpful info. It looks like the official manual they use in the workshop and it seems to be produced by BMW of North America.
Link to original post on zpost:
http://e89.zpost.com/forums/showthread.php?t=1415044
and the file on googledrive
https://drive.google.com/file/d/0BxW-0N8LT84fU0FDNFUwak9KM1k/view
Link to dropbox in case the other one gets removed:
https://www.dropbox.com/s/5qgtgwq1p756wa5/BMW%20Z4%20E89%202.8i%2C%203.0i%2C%203.5i%2C%203.5is%202009%20-%202016%20Workshop%20Repair%20%26%20Service%20Manual.pdf?dl=0
Link to original post on zpost:
http://e89.zpost.com/forums/showthread.php?t=1415044
and the file on googledrive
https://drive.google.com/file/d/0BxW-0N8LT84fU0FDNFUwak9KM1k/view
Link to dropbox in case the other one gets removed:
https://www.dropbox.com/s/5qgtgwq1p756wa5/BMW%20Z4%20E89%202.8i%2C%203.0i%2C%203.5i%2C%203.5is%202009%20-%202016%20Workshop%20Repair%20%26%20Service%20Manual.pdf?dl=0