FEATURING the same all-alloy 3.6-litre flat six that appeared across the 911 range when it was facelifted in August, 2001, the C4S produces a healthy 235kW at 6800rpm and a muscular 370Nm of torque at just 4250rpm - figures that are more often associated with a V8 than a six-cylinder. The updated 3.6 is itself a development of the first liquid-cooled 911 engine that appeared in the current, 996 version in 1998. Apart from benefiting from a 200cc increase in displacement, the new engine also features the Turbo's VarioCam Plus variable valve timing technology, the "Plus" part of which adds variable inlet camshaft timing to an already clever induction equation. In effect, VarioCam Plus provides low valve lift for part-load city traffic situations and high valve lift - said to deliver three times as much torque for maximum performance. The proof is in the driving: the new 3.6 is even more flexible than before, operating with impressive thrust over a rev range from around 1000rpm to almost 7000rpm. Combined fuel economy remains a respectable 11.4 litres per 100km, which is said to be a seven per cent improvement on the less powerful 993-series 3.6-litre engine. While top speed remains an impressive 280km/h, 0-100km/h acceleration is slightly down on the standard 911, due to the heavier drivetrain, at 5.1 seconds.