GM Prototype 1992 Oldsmobile Achieva Convertible. The car is a prototype convertible built by GM in 1992. This model was the first year for the Acheiva and I have all the documentation showing GM Prototype history. The car was purchased from GM after they went into Bankruptcy and were forced to sell all of their prototype and concept cars at auction to raise money. This is a one of a kind car and the only one ever created by GM. It is a 23 year old car that is brand new and only has 320 miles on it. Asking $16,500 or best offer.