M155

The SLR began on concept cars with a lightly altered M113 K, and arrived in production as something considerably harder. The block was reworked with a closed deck, the internals forged, the lubrication converted to dry sump, and a Lysholm twin-screw supercharger installed in the vee, spinning to 23,000 rpm for 0.9 bar of boost through a pair of intercoolers. The three-valve heads and 90° layout of the M113 carried over. It produced 626 PS at 6,500 rpm and held 780 N·m from 3,250 to 5,000 — driving, unexpectedly, through a five-speed automatic.

It weighed well over 200 kg and sat behind the front axle line, which is why the SLR's bonnet runs to almost two meters. AMG built each unit to its one-man-one-engine rule and shipped it to McLaren's carbon-fibre chassis in Surrey. The 722 Edition of 2006 raised it to 650 PS and 820 N·m, and the 722 GT track car to 680 PS. Its final outing was the 2009 Stirling Moss speedster — 75 cars, sold only to existing SLR owners — closing out a run of 2,157 cars and one of the last great European supercharged V8s.