New Mercedes E 300 e plug-in hybrid 2023 review

Big on comfort and technology, the plug-in hybrid E-Class looks set to be a fleet favourite…

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4.5 out of 5

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It’s likely to have a high list price, so the E 300 e might be a tough sell to private buyers. But for anyone considering a premium saloon as their next company car, there’s a serious amount of tech and comfort available here, and at a really appealing BiK tax rate. And better still, decent real-world electric range means that you could conceivably use your E 300 e as an electric car several days of the week – making it a proper bridge towards a full EV, and no mistake.

Time may be running out for combustion-engined premium saloons, but there’s no doubt that the latest generation of Mercedes E-Class is well positioned to help with the transition towards full electrification. We’ve already discovered how mild-hybrid technology helps to make the E 200 and E 220 d petrol and diesel versions extremely appealing – but the pick of the range for many company-car choosers will be this plug-in hybrid, the E 300 e.

There are two PHEVs in the range, in fact, both based around 2.0-litre four-cylinder petrol power, and a 127bhp electric motor that’s integrated into the nine-speed automatic gearbox. With the E 300 e, the petrol engine provides 201bhp, slightly less than on the outgoing version, and you’re restricted to rear-wheel drive. The more potent E 400 e will be four-wheel drive only, and have a 248bhp petrol engine. There is also, incidentally, an E 300 de diesel PHEV waiting in the wings, although we’ve yet to receive confirmation that British customers will be offered it.

Regardless of model, the PHEV’s battery is a hefty 25.4kWh set-up (19.5kWh usable), and Merc claims it will be able to take the E 300 e anywhere between 60 and 72 miles on electricity alone, depending on trim level.

The higher of these figures, and CO2 emissions of between 12g/km and 18g/km, ensure that the leanest E 300 e should drop into the five-per cent Benefit-in-Kind band for company-car tax. So even allowing for an expected price rise, in line with the rest of the range, higher-rate taxpayers could end up having this model on their driveways for a tax bill of around £100 per month.

Whether you’re a fan of PHEVs or not, that represents a hell of a lot of car for not a great deal of money. Because the good news is that in 99 per cent of situations, the E 300 e feels every bit as accomplished as its non-plug-in stablemates. It’s not a car focused on dynamic agility – head to your BMW dealer to talk about the forthcoming 5 Series if that’s your priority – but the E 300 e still has a fabulous relaxed gait to the way it cruises along, at pretty much any speed and across pretty much any road surface.

All of the vehicles available to us on Merc’s Austrian test event were fitted with optional air suspension, but even so, the way in which the E 300 e soaks up urban potholes, railroad crossings and even mid-corner bridge expansion joints is deeply impressive. Over the generations, Merc’s core premium saloon has been at its best when the engineers have honed in on ride quality – and every experience of the latest iteration indicates that it falls into this bracket.

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Admittedly, there’s the slightest increase in activity from the car’s rear end over bumps – just a little more patter, as the smallest of giveaways that you’re carrying a bit more weight in this version compared with the regular diesel and petrol – but unless you were to try these vehicles back to back (as we have), you’d struggle to really tell the difference. It hangs on well enough in corners, too, with nicely weighted steering and solid enough body control.

Of course, the transition between pure-electric and combustion power is another area where the E-Class could trip over itself, but again, it’s dealt with smoothly and efficiently. You can force the car to run in EV mode around town, then happily switch it to hybrid mode and barely notice the switch as the engine kicks in on, say, a motorway slip road. When it does, mashing the throttle will send the revs rising, revealing that it’s not the most characterful of notes.

But in truth, the electric assistance spares you from almost all of the drone, and once you’re up and cruising, it’s every bit as smooth as an E 200 – helped by an overall output of more than 300bhp and 550Nm, which means it has more than enough shove to cope with any extra mass. The brake modulation – the tricky blend of discs, pads and energy recuperation – is neatly executed too.

That EV range, and the ability to reach 87mph on electric power alone, mean that some people want to operate their E 300 e as a zero-emissions vehicle even when it’s running out of town or on motorways. Merc has anticipated this and as well as the standard 11kW three-phase AC charger, a 55kW DC system will be available as an option, allowing a full refill in 30 minutes.

The cabin, meanwhile, is every bit as accomplished as the regular E-Class’s. So you get the same combination of screens – a 12.3-inch digital instrument stack, then a 14.4-inch central display, with the option of an additional 12.3-inch panel in front of the front passenger. The tech is based on Merc’s next generation of infotainment and it’s deeply impressive, with connected elements that rival the usual Android and Apple smartphone ecosystems.

The rest of the interior is a Merc tour de force, with oodles of driver-assistance systems, well-judged materials throughout and, thanks to a 22mm growth in wheelbase, more comfortable rear accommodation than in many of Merc’s earlier S-Class limousines.

The single biggest compromise, in fact, comes in boot space, for 370 litres is a pretty modest figure for such a large vehicle (it’s nearly four centimetres longer than the outgoing E-Class) and down on the capacity of even the outgoing BMW 530e. It’s enough for most uses, although Merc’s trump card on practicality will undoubtedly be the E 300 e Estate, which is due in the first half of 2024.

Model: Mercedes-Benz E 300 e
Price: £65,000 (est)
Engine: 2.0-litre 4cyl turbo petrol hybrid
System power/torque: 308bhp/550Nm
Transmission: Nine-speed automatic, rear-wheel drive
0-62mph: 6.4 seconds
Top speed: 147mph
Economy: 353-565mpg
CO2: 12-18g/km
On sale: August

John started journalism reporting on motorsport – specifically rallying, which he had followed avidly since he was a boy. After a stint as editor of weekly motorsport bible Autosport, he moved across to testing road cars. He’s now been reviewing cars and writing news stories about them for almost 20 years.

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