European models were outfitted with a dogleg version with close ratios and a 1:1 ratio for fifth gear. The transmission was a Getrag 265 5-speed manual. The brake calipers, discs and master cylinder were unique to the M3 model. The only exterior body panels the regular 3 Series and the M3 shared were the bonnet, roof panel, sunroof. As a result, the M3 achieved a relatively low drag coefficient of C d=0.33 instead of C d=0.38 as in the standard 3 Series. In addition, the windscreen was glued in – not, as with the other E30 models, framed with a window rubber and piping. The changes over the rear of the car resulted in lower lift forces and better straight-line stability. For aerodynamic reasons, the rear window was flattened and the tailgate was made of light, glass-reinforced plastic raised by approximately 40 mm for better air flow. The front splitter, the rear apron, sill panels, as well as changes to the body in the area of the rear window ( C-pillar) and the bootlid improved the aerodynamics. The E30 M3 was mainly produced in the coupé body style, but limited volumes of convertibles were also produced. It was presented to the public at the 1985 Frankfurt Motor Show, and began production from March 1986 to June 1991. The first BMW M3 was based on the E30 3 Series and was intended to be a homologation special to satisfy the Deutsche Tourenwagen Meisterschaft and Group A Touring rules, which required a total of 5,000 cars to be built.
