Took a little bit of a gamble and bought a set of these for my summer/hpde car
https://www.turnermotorsport.com/p-2...t-m3-turner-mo
Even though it doesn't list Z4 non-M for fitment I can confirm it does fit, and has the desired effect. Just got it back from the alignment shop at -2.5 degrees camber in the front up from -1.5ish on the stock hardware with the alignment pin removed. Judging by the slots in the tower, could definitely have gotten more negative camber. Nothing mindblowing here, but hope it helps other E85/86 non-M folks. As this is not a dedicated race car I wanted more negative camber while retaining the stock rubber mounts... this was perfect for my use case.