Page1
http://workshop-manuals.com/bmw/z_se...t_coil_spring/
page2
http://workshop-manuals.com/bmw/z_se...ing/page_1206/
Here the inner drive flanges
http://workshop-manuals.com/bmw/z_se..._output_shaft/
(you don't have to remove the outer nut etc, just remove the inverted torx bolts from the inner diff flanges (the ones that hold the drive axles to the inner flanges)
If you're planning to do more work on your car I suggest you get a working copy of the TIS DVD (TIS= all BMW workshop manuals). It is extremely helpful as it has all the official procedures, tightening torques etc.
You can use lower springs (like eibach springs) with the stock shocks.
For the fronts you obviously need a spring compressor as it is a mcpherson strut.