Back in 1989, BMW first began selling their Z1 roadster, a small two-seater that served as an experimental test bed for several new technologies. Its subsequent ancestors were the Z3 and Z4 roadsters. Powered by the E30 325i's 2.5-liter straight-six with 170hp, the Z1's exterior design is particularly distinctive due to its doors which vertically retract into the body. Other notable traits include the plastic body which could be completely removed from the chassis.
In fact, owners could remove the body panels in a process that was originally designed to take roughly 60 minutes but in reality this turned out to be a two day job that only experienced mechanics could handle.
There were various aftermarket tuning programs available for the Z1 and demand supposedly remained fairly high when production ended in 1991. All told, around 8,000 units were produced and the car today still enjoys a loyal following. As you can see in this video produced by BMW, proud owners from throughout Europe journeyed to the automaker's headquarters in Munich to celebrate the Z1's 25th anniversary.