[legion]

GM owns them all, and has a long history of sharing models between divisions.

The Pontiac GTO was actually the Holden Monaro. The Astra is made by Opel, Vauxhal, and Saturn. The G5/Cobalt is rebadged by just about every division. Opel makes a version of the Sky/Solstice.

Then there are the models that GM purchases from other companies. The Saturn Vue is made by Honda (their version is called the Element). The Pontiac Vibe is made by Toyota (their version is called the Matrix).