SPY PICS: 2016 Mercedes-Benz E-Class

The E-Class that will take Mercedes-Benz back to the future has been spied testing in Germany.

Due on sale in 2016 in Europe, the all-new E-Class will deliver not only hybrids, plug-in hybrids and three- and four-cylinder engines to the venerable Benz mid-sizer, but will mark a return to in-line six-cylinder power, too.

It will be longer, wider, more spacious and cleaner in design than the current car, with five different body styles emerging to wear the E-Class badge.

Based around the MRA modular architecture Mercedes-Benz thatdebuted under the C-Class, the all-new E-Class will be available in sedan, wagon, coupe, convertible and long-wheelbase sedan forms.

Unlike the current versions, the new E-Class's Coupe and Convertible will actually sit on the E-Class's underpinnings (the current E-Class coupe and convertible are actually C-Class underneath the skin), while the long-wheelbase version is headed for worldwide consumption and not just China.

The CLS, which is basically a rebodied E-Class with better steering, will follow the E-Class sedan by a year, while AMG's E 63 is also on the books.

The standard version will have a longer wheelbase and shorter overhangs than the current car, with Mercedes keen to push the front and rear tracks wider to turn its traditionally conservative technology leader into a dynamic leader on the road.

Sadly, it won't lose any weight in the changeover to the new layout, even though it will boast an unprecedented level of aluminium and other lightweight metals throughout the stiffer, more rigid bodyshell.

That's partly due to the extra size and dimensions of the car and partly because of the extra equipment it's expected to take on board.

Its styling is expected to shed the angular, slightly disjointed look of the current model in order to sit more rationally between the C-Class and the S-Class, with the design language said to be closer to the smaller model.

Inside, Mercedes-Benz will offer some astounding equipment as either standard or optional features as it expects the E-Class's interior to build off the stunning C-Class cabin.

There will be an augmented-reality head-up display, plus the S-Class's Magic Body Control and a temporary autonomous driving option that is expected to let drivers step out from the car so it can park by itself.

There will also be the S-Class's two 12.3-inch TFT colour monitors to dominate the dashboard, though they will be more thoroughly integrated into the layout than the flagship's hastily-fitted versions.

Long lamented around the technical halls of Benz's Sindelfingen headquarters, the inline six-cylinder was the cornerstone of Mercedes-Benz's entire brand until it was replaced by the coarser tones of V6 power in 1998.

Engineers at Mercedes-Benz have been pushing to get the smoother, sweeter-sounding engine layout back beneath the E-Class's bonnet ever since, and they've finally succeeded.

Interestingly, it took a lesson learned from cross-country rival, BMW, to spark the re-revolution at Mercedes-Benz, with the world's oldest car-maker now using BMW's single-cylinder modular formula to create the inline six.

Like BMW, the engine will be based around a single cylinder, roughly 500cc in capacity, which will be turned into inline three-, four- and six-cylinder powerplants.

The modular formula will be used for both petrol and diesel power, with the two hugely disparate engines believed to share around 60 per cent of their parts, sources at Mercedes-Benz insist.

The petrol versions will come in both naturally aspirated, turbo and twin-turbo layouts, producing between 150kW and 320kW of power, while the diesels will focus on torque, with up to 600Nm on the most powerful twin-turbo diesel.

Thankfully, the V8 will survive into the next generation of E-Class, with a development of the current 5.5-litre biturbo V8 being joined by the AMG V8, based around the AMG GT's 4.0-litre biturbo motor.

The new engine family will be mated to the nine-speed automatic transmission, which is already in service in the E 350 BlueTEC, and will come in both rear- and all-wheel drive. For the first time, its all-wheel drive version will be available in right-hand drive layouts.

The transmission will also play host to the disc-shaped electric motors that will drive the hybrid and the plug-in hybrid, the latter of which is expected to improve on the S 500 Plug In Hybrid's 33km of pure electric running and stretch that out to 50km.