Available to order in the UK from April, with deliveries beginning in the summer, the S65 Cabriolet receives the same upgraded twin-turbocharged 5.5-litre V12 as the recently introduced S65 Coupé.
Now assembled at parent company Mercedes-Benz’s factory in Mannheim rather than on site at AMG’s Affalterbach headquarters, the three-valve-per-cylinder powerplant produces 621bhp at 4800rpm along with 737lb ft between 2300 and 4300rpm.
The reserves are channelled to the rear wheels through a seven-speed automatic gearbox with three drive modes: Controlled Efficient, Sport and Manual. The car sits on standard 20in wheels shod with 285/35 tyres.
Despite carrying an extra 175kg brought on by the added bracing incorporated within its platform, Mercedes-AMG says the 2180kg S65 Cabriolet boasts the same 0-62mph time as the 2035kg S65 Coupé at 4.1sec.
This is 0.2sec slower than the 2110kg four-wheel drive-Mercedes-AMG S63 Cabriolet 4Matic, whose twin-turbocharged 6.2-litre V8 produces 577bhp and 663lb ft.
Top speed for the new AMG model is nominally limited to 155mph, although buyers can choose to raise it to 186mph with an optional Driver’s Package that includes uprated tyres. Combined cycle fuel consumption is put at 23.5mpg, with CO2 emissions rated at 272g/km.
The range-topping S65 Cabriolet is visually differentiated from other S-Class Cabriolet models through its more liberal use of chrome within the air ducts incorporated in the front bumper, a unique wheel design, V12 bi-turbo badges along the flank, a high gloss black diffuser, quad-trapezoidal shaped tailpipes and S65 identification at the rear.
The multi-layer fabric roof is available in black, dark blue, beige and dark red. It can be opened and closed on the move at speeds of up to 31mph, with the whole process taking a claimed 17sec.
Inside, the luxurious new four-seater receives Mercedes-Benz’s Aircap wind protection deflector, Airscarf heating elements in the backrests of the front seats and heated armrests among a raft of upmarket features, all of which are carried over from the S65 Coupé.