M139 is a rear wheel drive automobile platform developed by Maserati for use in a range of vehicles in the Fiat group. It underpins the 2004 Maserati Quattroporte, 2007 Maserati GranTurismo as well as the 2010 Maserati GranCabrio and also forms the basis of the 2007 Alfa Romeo 8C. It uses four-wheel independent suspension, composed of double wishbones on both axles.
A shorter version of the platform was evaluated to underpin the 2013 SRT Viper, but was not chosen.
References
Maserati M139 platform Wikipedia(Text) CC BY-SA