You need a four-digit-horsepower convertible in your life.

With a twin-turbo 4.0-liter V8 engine pushing out a monstrous 603 horsepower, you’d think the Mercedes-AMG S63 Cabriolet is not the kind of car that could use a bit more oomph. The German tuners at Posaidon see things differently as they’ve just introduced what is easily one of the most powerful four-seat convertibles in automotive history.

This is actually the pre-facelift S63 model, so it uses the old twin-turbo 5.5-liter V8 engine with 577 horsepower and 664 pound-feet (900 Newton-meters) of torque on tap. However, the displacement has been bumped to 6.3 liters and some of the hardware had to be reinforced. There are now new steel bushings for the cylinders, along with an updated main bearing line, a tweaked compression ratio, and reinforced valve springs.

See how other tuners have customized the S63 Cabrio

Needless to say, the two turbochargers have also gone through a few changes and Posaidon fitted the droptop Mercedes with a custom air kit, sports air filter, and a new radiator. The engine’s electronics also had to be modified, while the differential locks as well as the seven-speed automatic transmission were modified to cope with the extra power.

The end result is a luxurious convertible just about as powerful as the mighty F1-engined Project One. The engine now produces an incredible 1,005 hp and a peak torque of 1,033 lb-ft (1,400 Nm). Thanks to the newly gained muscle, the S63 Cabriolet now needs just 2.9 seconds to go from 0 to 62 mph (100 kph) and will continue to accelerate until an electronically governed 218 mph (350 kph).

It goes without saying the power upgrade is available for all the other Mercedes-AMG models fitted with the twin-turbo 5.5-liter V8, so if you happen to have an older generation E63, ML63, GLE63 or a G63, the engineers from Posaidon can unlock four-digit horsepower. Same goes for the now defunct CLS63.

Source: Posaidon

Gallery: Mercedes-AMG S63 Convertible by Posaidon