The Cart Before the Horse: Spec 3 Build

[D_Eclipse9916]

2 ball joints per front control arm (you can press E30 M3 ball joints in E36 M3 arms, but you don’t have the arms to begin with)
2 ball joints in rear per side for upper and lower arms
RTABs and corresponding reinforcement washers

Those are all critical, no ifs and or buts. If you are in there though... might as well do subframe bushings/ sway bar reinforcement/ rtab reinforcement and diff bushings. This is assuming this is the car you are taking to race. If not just do bushings/ball joints and watch those areas carefully. RTaB failure is what demolished my E46..