It is best not to look too closely at the headline performance figures we recorded for the CLS 63. We picked our moment to visit the test track as carefully as possible but couldn’t avoid showers that meant the Mercedes wanted to spin its wheels all the way through first, second and into third gear.
AMG claims that this car can reach 62mph in 4.1sec and the Shooting Brake in a leisurely 4.2sec. We managed only 5.2sec to 60mph in the coupé, but given that we spent half of that time reaching 30mph, we don’t doubt the 4.1sec claim one iota.
Despite the tardy start, our test CLS posted a sub-10.0sec time to 100mph and had no trouble running into its 155mph speed limiter before we needed to brake at the end of MIRA’s mile-long horizontal straights.
Make no mistake: the CLS 63 is comfortably in the top division of saloon performance.
Given the hindrances to its standing-start performance, the in-gear figures make for more representative reading. To reach 70mph from 30mph takes just 3.6sec, and 5.6sec in fourth gear. Fourth is good for adding 20mph to your speed in less than three seconds all the way to 110mph. Third gear can add 20mph in less than two seconds almost all the way to its limiter.
All of which would be impressive even if the engine wasn’t as breathtakingly charismatic as it is. It fires with a deep, bellowy woof (rather often in traffic, given that it has a stop-start system that must sound ludicrous to the outside world), idles smoothly and menacingly and growls like the best of them on full throttle.
Presumably, the turbochargers muffle the exhaust sound a little, but given how good this car sounds from the outside, it can’t be by much. Neither do they spoil the throttle response a great deal. Only if you get caught at low revs on a track will you notice any lag.
The seven-speed gearbox just about gets the best from it. It’s a single wet-clutch automatic unit (which also sees action on the SL 63), and although it shifts intelligently if left on its own and is smooth in daily driving, it wouldn’t hurt if the paddles gave slightly quicker downshifts.