On this episode of Head 2 Head, Motor Trend's Jonny Lieberman pits the 2013 BMW M5 against the 2013 Porsche Panamera GTS in an epic super sedan showdown. The battle begins in California's Mojave desert with a classic quarter-mile drag race. Then Jonny takes both V-8 powered sports saloons up to Big Bear, California to find out which one carves up the winding mountain roads the best. Head 2 Head appears every other Wednesday on the new Motor Trend channel. www.youtube.com/motortrend Subscribe now to make sure you're in on all the action! www.youtube.com/subscription_center?add_user=motortrend Facebook - facebook.com/motortrendmag Twitter - twitter.com/motortrend Google+ - plus.google.com/101867967859016552744/posts Website - www.motortrend.com