This is the new 5.5-litre V8 that made its debut in the S-class at the end of last year. It means power rises from 310bhp to 383bhp and torque output is 391lb ft.
In fact, the SL has had a deceptively subtle makeover in most areas. There's a blink-and-you'll-miss-it new grille and bumper treatment, new rear lights and redesigned wheels - like many of its wealthy owners, the SL is ageing gracefully.
Changes are similarly subtle inside: some materials have been upgraded and there's a new binnacle for the dials. Small paddles behind the steering wheel indicate this car has the Sport version of the new 7G-Tronic seven-speed automatic gearbox that has a 'manual' mode with 30 per cent quicker shifts than the auto.
What's it like?
A new exhaust may be one of the smaller changes made to the facelifted SL, but the soundwaves emitted from the tailpipes of this SL 500 have a thunderous edge of menace.
The gearbox is a fine match for the SL's smooth demeanour, but as we've remarked before, on occasion you sense it has almost too many gears to choose from. It's also a pity that it insists on changing up at the red line when you're in manual mode, as a higher gear can be the last thing you need when entering a braking zone at speed.
Mercedes has given the SL's character a more sporting agenda: the active suspension system has been revised, with body movements said to be checked by up to an extra 60 per cent in sport mode; the steering is more direct, with reprogrammed assistance and a new pump; and there are larger brakes.
While the driving experience still lacks detailed feedback, the SL resists roll keenly and has plenty of grip, although a little more progression in the early stages of throttle travel would be welcome.
Should I buy one?
SL buyers won't take a second glance at the price rise of £1755, and these revisions have only added to the car's considerable appeal.