The changes to the 2011 Mercedes-Benz CL63 AMG are subtle but significant.

While it may not be quite as familiar as the well-known S-Class, the Mercedes-Benz CL coupe is arguably the brand’s flagship, both a styling and technology showcase.

And the top-line German coupe will be getting an updated look for 2011, as you can see from these, a pair of the first shots to emerge from Mercedes headquarters, in Stuttgart.

As with most AMG versions, the details are surprisingly subtle.  The most obvious changes for 2011 with the Mercedes-Benz CL63 include a more aggressive front fascia, new side skirts and the distinctive new quad exhaust ports.

Of course, what real performance aficionados are most likely to care about is what AMG has done under the hood, and for 2011, it seems, the CL63 nomenclature is a bit misleading.  The coupe will now be powered by a 5.5-liter biturbo V8 making an impressive 563 horsepower and 664 lb-ft of torque – with the optional AMG Performance Package.

In standard trim, output is a still-solid 536 hp and 590 lb-ft of torque.

Top speed is 155 mph -- 186 with the optional AMG Performance Package.

Either way, the direct injection, twin turbo package is now equipped with fuel-saving Start/Stop technology, which will permit the engine to briefly shut off at a stoplight then automatically start back up when the driver’s foot lifts off the brake pedal.

The engine will be mated to the AMG Speedshift MCT 7-speed sports gearbox.  It offers three different driving modes – as well as a rev-matching function.

The use of direct injection, Start/Stop and other features will yield a 27% increase in fuel economy, Mercedes claims.  But don’t expect that to show up in the performance numbers.  The Performance Package will launch from 0 to 60 in 4.3 seconds, the “base” model  coming in just a tenth of a second slower.  Top speeds jumps from an electronically limited 155 mph to 186 in performance trim.

We’ll get a look at the actual sheet metal in about two months, at the biennial Paris Motor Show.  The 2011 Mercedes-Benz CL63 AMG will roll into showrooms in November.