Rogue Engineering Billet Aluminum Chassis Support V-Brace Kit - E46 M3An integral part on E46 M3 is the rear chassis "V Brace" (BMW # 33 31 2 229 899) found on all 2001 06 Convertibles and Coupe (including the CSL). This brace attaches to the outward points of the rear chassis and to the area near the rear subframe carrier. Since some of these vehicles are now over 20 years old, we have been seeing more and more of these start to rust away. The OE V brace is made from 38mm x 12mm (1. 5" x 0. 5") hollow square steel