The report cites a high-ranking Mercedes engineer who claims the car will have reserves to "equal those of the existing S63 4Matic", which is powered by a 450kW/900Nm 4.0-litre twin turbo V8 engine.
No surprise then, the Autocar report suggests expected outputs could produce more than 600bhp (447kW) and 663lb-ft (898Nm). The price tag would of course be substantial, given the non-AMG EQS is expected to eclipse the $200,000 mark, while the AMG S63L is priced from $393,000 in Australia.
The AMG EQS should also neatly better the 'regular' EQS concept's 0-100km/h time of 4.5 seconds – and likely also that of the S63L's 4.3-second run.
CarAdvice approached Mercedes-Benz for confirmation, but representatives were unable to comment on the reports.
The EQS, which lives in the same large limousine class as the established S-Class icon, made its debut in concept form at the 2019 Frankfurt Motor Show. A production model is expected to go on sale in the next two years, promising a 700km driving range and a 0-to-100kmh time of 4.5 seconds.
It will join the already available EQC SUV and incoming EQA small SUV, EQB crossover and EQV van in Mercedes-Benz's fully-electric EQ range, which will also eventually include an electric G-Class off-roader and a smaller EQE upmarket saloon.
Autocar reports the latter two are likely to share the same high-performance driveline as the AMG EQS.
Mercedes-Benz has been clear about its plans to become fully CO2-neutral in the next few years, with Mercedes-Benz Cars CEO and Daimler AG Chairman Ola Källenius detailing plans to unveil a host of electric cars in the near future.
"It is true the cost structure of electric vehicles is higher than what we are used to on combustion-based vehicles. [But] we feel as volumes go up, from tens of thousands of vehicles to hundreds of thousands of vehicles, we can start reaping benefits of scale," Mr Källenius said.
"We have made full commitment to writing the electrical chapter."