I just installed the 335i Eibach Pro Springs in my XI on Thursday (stock struts/shocks). They definitely tightened up the handling and took care of the excessive wheel well gap.
As far as the ride... It's definitely much firmer and rides just fine on normal, flat road conditions. But! Any good dip or bump, you'll feel for sure. Shocks bottom out easily.
Long story short... I will be ordering struts/shocks ASAP.
2017 M4 /// YMB-Blk /// 15% Tint /// M-performance Grills /// CF M-Performance Splitters /// CF M-Performance Trunk Spoiler /// CF M-Performance Front Lip /// Color Match Reflectors /// Keyhole Delete