Chassis Reinforcement Plates

[MattDearPhoto]

Thinking of doing these, which ones are really necessary and which
ones do the M3 have that the standard car doesn’t?

[Nate047]

I don't know what the differences are between M and non M, but on 96+ M3s you want to do rear sway bar mounting tabs, RTAB pockets, rear shock upper mounts, and you do not need to worry about the floor pan in general like you do on an e46. Early cars might be different. some people also do front subframe reinforcement plates, probably a good idea if it's a track car.

[TexaZ3]

Might want to throw on an x-brace under the front of the engine as well.

[MParallel]

The M3 has the 4 rear axle and 2 gearbox reinforcements.

[M3AN]

Some early M3's, don't know when, didn't have front shock tower reinforcements, these are easy to add (no welding). Also later cars had the front subframe reinforced (at the engine mounts) but big washers under the engine mount bolts will suffice.

As above, Z3 or equivalent rear tower reinforcements (bolt on), rear trailing arm pocket reinforcements (weld on), especially if you have poly bushes (look on YT to see what happens when one lets go) and rear sway bar mounting tab reinforcements (weld on), especially if you have uprated sway bars. Years of worry-free auto-xing.

[MParallel]

March 96 (so halfway point of MY96) the front reinforcement plates were introduced.

The Z3 rear reinforcement plates are such a must-have. Very cheap and super easy to fit. You'd be almost stupid not fitting them.