Before roadsters like the Z3, Z4 and the cool-looking, limited production Z8, BMW introduced the strange looking but interesting Z1. The Z1 was a sleek roadster with uncharacteristic styling and plastic body panels. Also, it had unusual sliding doors, which disappeared in rocker panels when drivers opened them. Technically, you could drive the BMW Z1 with the doors down.
The other interesting feature was the plastic body panels bolted onto the chassis. Z1 owners could buy different color panels and attach them to the car at their will. That means they could change the color of the car just by adding different colored doors and fenders, as well as the trunk or hood.