The North American Subaru Impreza Owners Club have posted pictures of what looks to be a four-door Cadillac CTS Convertible. The right-hand drive test mule was caught in Detroit. Being a right-hand drive vehicle, the test mule may be something GM is working on for the European market.
GM recently took control over the sales and the future of the Cadillac in Europe.
Cadillac CTS Sedan Convertible Spy Shots Gallery:
Source: NASIOC (via Jalopnik)