Just did this for my fronts today. Ran out of daylight to do the rears.
Just a heads up!
The front springs are literally almost twice as large as the H&R's (I have the sport springs) so compressing the stock spring (in this method) will by far be the hardest part.
Everything else is very straightward and easy.
http://www.ecstuning.com/BMW-E92-335...1/Video319-HD/
This video made the rear install so much simpler in my opinion. I LOVE ECS TUNING!!!!