Mercedes-AMG has explained why the mid-cycle refresh of the E63 S super-sedan didn’t include a power hike.

While Affalterbach’s facelifted E63 S saloon gained a handful of styling and aero revisions plus some under-the-skin tweaks to ostensibly improve comfort levels, the twin-turbo 4,0-litre V8 was left untouched, delivering an unchanged 450 kW and 850 N.m to all four corners.

Drummond Jacoy, Mercedes-AMG director of overall vehicle development, told Motor1.com the firm didn’t want the E63 S to tread on the toes of a certain sibling.

“To emphasize the driving capabilities, it wasn’t just a case of pure numbers. We were very happy with the engine size and driving characteristics,” he said.

“We have a car line-up, and above the E63, we have the GT63 S, and we don’t want to have an overlap there, so we kept additional power exclusive to the GT63 S,” Jacoy explained.

Interestingly, the executive also told Motor1.com the company opted not to add its “EQ Boost” mild-hybrid system to the mix since the associated integrated starter-generator (ISG) would necessitate the adoption of a torque-converter transmission.

“The E63 has specific characteristics. We want [launch control]; we want very, very precise shifting. To do that, we use an electromechanical clutch rather than a torque converter,” he said.

“We have package constraints, so we decided to stick with the original powertrain as it was set up. We just couldn’t get the ISG in there.”

As the publication points out, however, it’s not like the E63 S is sluggish, with Mercedes-AMG claiming a 0-100 km/h sprint time of 3,4 seconds and an electronically governed top speed of 300 km/h.