In a few days the all-new 2013 Mercedes SL will make its world debut at the Detroit Motor Show. On this occasion Mercedes USA released a new promo video, which does a good job summarizing all that’s new about the SL. The headlines include an all-aluminum body which is 140kg lighter than the previous model, new wiper nozzles, and a front bass system. The car does have a controversial design though, there’s no denying that.