What may be the world's most expensive mobile tire test bed, the Maybach Exelero Concept, is being offered for sale at a starting price of €5,000,000 ($7,843,000). The retro-futuristic twin-turbo V12 concept car is capable of sprinting to 100km/h in 4.4 seconds and a top speed of 351km/h (218.38mph),impressive figures for such a large and imposing car.

Built to order for Fulda Tires as a rolling test platform and marketing tool for its widest, most high-performance tire designs, the Exelero is built around a heavily modified powerplant from the Maybach 57 S. The engine generates 700hp and 738lb-ft of torque from its bored-out 5.9L displacement. Fitted in some guises with 23in 315/25 tires, the car certainly has the capacity to test just about everything that could feasibly be fitted to a production car.

The car was unveiled for the first time ever at the Tempodrom in Berlin in May 2005. The car's form factor is a long-nose two-seater coupe, and the interior is a unique marriage of ultra-high luxury and full-race safety gear. The car's top speed of 351km/h (218.38mph) isn't claimed, either - it's proven, recorded at the Nardo high-speed test track in Italy. To see the car in action at Nardo and elsewhere, check out this video.