It looks like the Germans from Hamann will introduce the most powerful tuning program for the 2012 BMW M5 this year in Geneva.
They should steal the crowds away from other tuners such as AC Schnitzer or G Power, as their kits will only enable the new M5 F10 to produce 620 and 640 HP respectively, whereas the Hamann program has turned the German saloon into a 720 HP beast.
The car will also develop a total of 900 Nm of torque, which means 160 HP and 220 Nm more than the standard M5.
Hamman has also applied a more aggressive makeover to the 2012 M5, and we are talking about a custom body kit and various carbon fiber elements such as mirror casings, door handles, side vents, roof spoiler and more.
The Hamann 2012 BMW M5 comes with 21 inch double spoke design rims, a 4-pipe sports exhaust, a 30 mm lower suspension and a two tone interior enhanced through the addition of a sports steering wheel, aluminium pedals, and various other unique touches.    

Source: Hamann