My neighbour has just finished his 1968 Holden Monaro. Last Sunday we took it out for a drive with our car club. I made sure to park my 1968 Opel Commodore next to the Monaro. As you can see there are striking similarities between the two GM cars [certainly from a distance]. I guess the biggest difference is the big V8 in the Monaro's favour. On the other hand I believe the lines of the Commodore to be more refined. They are both nice classics though!