The Mercedes CLS63 AMG has been given a mild power upgrade, with peak power lifted from 518bhp to 549bhp.

Despite the extra performance, emission levels and fuel consumption remain unchanged. Mercedes claims the 5.5-litre twin-turbocharged motor is the most efficient series production V8 currently available.

A new range-topping S version has also been introduced; sporting 577bhp and Mercedes’ 4MATIC all-wheel drive system, which is now available as an optional extra across the CLS AMG range.

While limited to a top speed of 250kph, the CLS63 AMG S will cover the 0-100kph sprint in 3.6 seconds, an improvement of 0.6 seconds over the standard car.

S models also come fitted as standard with a rear locking differential, something which was previously only available in conjunction with an optional performance pack.

While the S model has been confirmed for the German market, there is as yet no confirmation as to whether they will be made in other global markets.