Xdrive and RWD with sport have different stock ride heights. The Xdrive sits much higher.
I have yet to hear of a satisfied Xdrive owner who lowered with springs. They all revert to the original oem suspension or invest in coilovers. The Xdrive suspension set-up is just different, so research carefully before doing anything.
I recently drove a 535Xi Touring with KW V3 coilovers. Just amazing. It was lowered 1 inch. Huge improvement all the way around.
Styling: M5 body kit, M5 trunk spoiler, LED Angel Eyes, HID fogs, LED side markers, Jehnert Flatline speakers, Mobridge M1000 DA2 prepro, Zapco Z8 DSP, Zapco Z-150.6 amp, iDock on dash
Performance: JB4/G5 ISO flashed on Cobb, Meth Injection, AR Downpipes, ER FMIC and Charge Pipe, DCI, Walbro LPFP, RB turbos. H&R Sport springs/Koni FSD shocks.