The side panels and doors are made of GE's Xenoy thermoplastic. The bonnet, boot, and roof cover are GRP components made by Seger + Hoffman AG. The car is painted in a special flexible lacquer finish developed jointly by AKZO Coatings and BMW Technik GmbH. During the Z1s launch, BMW suggested that owners purchase an additional set of body panels and change the color of the car from time to time. The car could actually be driven with all of the panels completely removed, similar to the Pontiac Fiero. BMW noted that the body could be completely replaced in 40 minutes, although Z1 owners have reported that this may be highly optimistic. Aerodynamics were a focus of the vehicle design. The flat plastic undertray is used for ground effect aerodynamics and the rear bumper - in conjunction with the aerodynamically shaped muffler - forms a diffuser to reduce rear lift. The front end reportedly induces a high-pressure zone just forward of the front wheels to increase front-wheel traction. The Z1 has a drag coefficient of 0.36 Cd with the top up or 0.43 Cd with it down. Suspension The rear suspension, called the Z Axle, was specially designed for the Z1. It was one of the first BMWs to feature a multi-link design. In the 1990s, the Z Axle would be used on a variety of BMW Group vehicles, including the E36 3 Series and the R40 Rover 75. Front suspension is as per the E30 325i. Wheels, similar to the E30 325i, are by wheels on both the front and rear, equipped with 205/55VR-15 tires. Drivetrain The sole drivetrain configuration is a 2.5 Litre M20 straight-six engine and five-speed Getrag 260/5 manual transmission, sourced from the E30 325i. The engine is a SOHC straight-six engine, which produces at 5,800 rpm and of torque. The engine sits tilted 20 degrees to the right, to accommodate the low hoodline. Z Series The "Z" in Z1 originally stood for , the German word for future. Later cars in the Z Series are the Z3, Z4, and Z8, which were all available as 2-seat convertibles (however some models were also available as 2-seat coupes). Production The Z1 was produced from March 1989 to June 1991, all at BMW's plant in Munich, Exactly 8,000 cars were produced. All the cars were left-hand drive, and the majority (6,443) were sold in BMW's native German market.