Arguably the most insane production vehicle built in the last decade, the Mercedes G63 AMG 6x6 is an absolute monster. Mercedes aftermarket firm Carlsson obviously thinks it's not monstrous enough, so it has created a tuning program that includes a CK63 performance kit. This adds an extra 106 horsepower and 103 lb-ft of torque, boosting output of the 5.5-liter twin-turbo V8 to 650 hp and 664 lb-ft of torque.

In addition, the German car stylist offers a bespoke interior upholstered in leather and Alcantara, with wood and carbon-fiber trim, alloy pedals, illuminated door sill plates, sheepskin floor mats and aluminum door-lock pins.