My Bil Sports and Bav Auto springs are a big improvement over the stock setup. My car corners with much less body roll with this setup. The only time I encounter bottom out is when I fail to slow down for RR crossings and bad road irregularities. I suspect the Sachs kit is the best way to go based on the board members who have tried several combinations before buying the Sachs kit but I'm quite satisfied with the BA/Bil Sport setup I'm currently using. I guess a lot depends on what one wants from the suspension.
John R
1992 525 IA, EAT chip, 16 x 7.5 Rondell 58's, BavAuto Springs, Bilstein Sports, Elipsoid Smileys & fogs, Z3 Pistol grip shifter, 4 VDO gauge package, Azure Blue w/nice patina - clearcoat shot