When it comes to needing an ultra-high-performance engine off the shelf, one of the most effective ways of securing one is by knocking on the door of Mercedes-Benz. Some of the most rabid supercars in automotive history have featured powerplants sourced from the legendary German automaker, with one of the best examples being Pagani’s range of Huayra and Zonda models, which used Merc V12 units in various states of tune.