You may have other issues but you certainly have failed lower control arm bushings.
I do not recommend replacing with stock bushings. Instead... stock bushings from a 96-99 M3 are (just about) solid rubber. They are also centered so the suspension geometry remains unchanged.
Pre-Pressed OEM Lemforder M3 Bushings The 95 M3 offset bushings would work but they increase caster (good), move the wheel forward in the fender opening (may cause clearance issues depending on wheel/tire combo) and require an alignment as the toe will change with the caster adjustment.