Rising development bills and ongoing delays have reportedly put the programme under serious review.
Mercedes describes this as the most comprehensive update the S-Class has received within a single generation.
Pricing is still to be confirmed, but the S will slot between the standard Continental GT at R5,2m and the Speed at R6,5m.
Electrical assistance will push output beyond the current 444 horsepower figure.
With just three examples planned, it is destined to become one of the rarest creations in Pagani’s 26-year history.
Tobias Sühlmann began his career at Volkswagen, but it was his time at Bugatti, Aston Martin and Bentley that helped establish his reputation.
They have confirmed a substantial investment to keep the legendary EA888 2.0-litre turbocharged four-cylinder alive and kicking.
Power is expected to come from a new twin-turbocharged 4.0-litre V8 featuring a motorsport-inspired flat-plane crank.
That is over 12 times the sticker price.
Demand is already strong, with more than 50 of the 150 cars accounted for by customers.