Non-m = replaceable ball joints
95 m3 = non-replaceable ball joints, all else same (increased caster achieved with offset bushing)
96-99 m3 = non-replaceable ball joints, increased caster achieved with different geometry of control arm, centered control arm bushing
Best compromise for ride comfort and optimum geometry is most likely the 96-99 CA with appropriate CAB (don't have direct experience but my intuition is jedi-like with this shit).
S52|ZF|TRM Coilovers 670/895|Staggered 18" 5's