Now that its archrival, the BMW 3-Series, has been completely redesigned, a new Infiniti G model is due for 2014. And now we have spotted the first mules out testing on public roads. Seen here under the modified body of the current generation, these chassis and engine mules were just spotted in Northern Sweden. As we can see, the track will become slightly wider and there are also extra air intakes in the front bumper just under the grille.

These extra intakes could be due to the fact that these prototypes are diesel powered. They were also seen going in and out of a Mercedes-Benz test facility in the area. So why is that relevant? We know that Mercedes-Benz and Renault have a partnership which now includes Infiniti. They are joining forces on various engine technologies, such as Mercedes diesel engines. The German automaker's BlueTec diesel units have been a huge success and it's not surprising that other automakers would be interested in that technology. No other details are known just yet, but Infiniti certainly has a major benchmark to defeat if it wants to become the segment leader.