Mine's an XI, so not sure if it sits any different than RWD, and sitting on smaller tires than stock (235/40/19 & 265/35/19).
BMW F10 550xi M-Sport - H&R Drop by
ONEighty_NYC, on Flickr
BMW F10 550xi M-Sport - H&R Drop by
ONEighty_NYC, on Flickr
BMW F10 550xi M-Sport - H&R Drop by
ONEighty_NYC, on Flickr
Here's how it sits on OEM 19's with 255/40/19's all around (my winter setup).
DSC_8322 by
ONEighty_NYC, on Flickr
DSC_8440 by
ONEighty_NYC, on Flickr
Here's a comparison
comparison by
ONEighty_NYC, on Flickr
Honestly, I would never go with anything but H&R springs, had them on all my cars and have installed hundreds of other brand springs on various cars for my customers and I would never consider anything but H&R. The ride feels like stock, but the car sits lower... and since its a little lower, the lower center of gravity tightens up the ride just a tad bit, but you get used to it just within a few days and it feels exactly like it did with stock suspension.
As for bounciness... I installed these on a NYC car with 43K miles, and I have yet to experience any bounce or increase in body roll (from stock). I'll tell you right away though... after 20K miles, you will notice a difference, and the shocks will go sooner than they would with stock, but its with any springs.
TECHNICALLY speaking, the rule of thumb is to upgrade your struts when you lower the car with lowering springs, in which case I'd recommend Belstein's, but I don't see a point of spending the extra money on struts, at least not till the stock struts start going.
Don't hesitate, get them... and you won't regret it.