The factory installed an additional underbody cross-brace on the front end of all E36 convertibles, the M3 Lightweight, and even the Z3 to strengthen the structural rigidity of the chassis. It is therefore understandable that all E36 models can benefit from the addition of this brace, which is why this has become recognized as a common upgrade. Installation is fairly straight-forward, especially for E36s manufactured after 10/94 due to the presence of the rivet nuts necessary to mount this brace.
Front End Underbody Cross X Brace Reinforcement (factory-installed on E36 convertibles, Z3 & M3 LTW), BMW 3 Series (1992-99) Brand: Genuine BMW [More Info]
Rivet Nut - M8 (4 req. for X-Brace), each Brand: Genuine BMW [More Info]
Hex Bolt with washer, M8X20-Z1, each Brand: Genuine BMW [More Info]