By LAWRENCE TAN

Before parting ways in 2009, Mercedes-Benz and McLaren have unveiled yet another variant of the Mercedes-Benz SLR McLaren Roadster 722, this time with an ‘S’ added behind the name.

Essentially, it is a convertible version of the 722 with a semi-auto soft top. It inherits the same supercharged 5.5-liter V8 engine from its fully clothed cousin, but tweaked by the engineers from Mercedes’ AMG division to output 641bhp from 617 bhp, and 605 lb ft of torque from 575. This propels the 722S from rest to 100 km/h in 3.7 seconds, and top speed has been increased to 335 km/h.

The engineers from Affalterbach have also made the spring and shock absorber configurations stiffer, and lowered the suspension by 10mm front and rear to achieve greater handling stability of the car. The fully carbon-fiber monocoque bar two aluminium frames stem from McLaren’s F1 expertise, and gives the 722S a torsional rigidity despite its lightweight.

The aluminium-reinforced soft top is semi-automated, which means to close it, you would have to manually unlatch the roof at the windscreen frame, give it a slight lift, and the electronics take care of the rest in about ten seconds.

Only 150 editions of the 722S will be made, and first cars are expected to roll out of McLaren’s F1 workshops in Woking, England come January 1, 2009.