This SLC 300 AMG Line is one step below the proper SLC 43 model in the range, offering perhaps a taste of AMG performance with a more palatable price tag and improved economy.

Engine, gearbox and 0-60mph time

In the past, the ‘300’ legend might have referred to a V6, but in this world of downsizing (and so as not to step on the toes of the AMG SLC 43) the SLC 300 sports a 1991cc, turbocharged inline-four.

It’s modest in output next to the AMG fours in A-classes and the like, delivering 242bhp at 5500rpm, but torque of 273lb ft from 1300rpm and a nine-speed 9G-Tronic automatic transmission mean it’s typically in the right gear at the right time for adequate performance. On paper, it’ll launch the SLC to 62mph in 5.8 seconds, while top speed is an electronically-limited 155mph.

On the road it never feels truly fast - that power figure has long been eclipsed by hot hatchbacks, and the 300 weighs in at 1505kg so it’s not a light car - but it moves smartly enough. Treat it as a stylish cruiser rather than a sports car (the SLC 43 exists to fulfil that role) and you’ll be happy enough.

Technical highlights

That 9-speed automatic transmission is probably the most interesting technical aspect of the SLC. Among its benefits are compact size and light weight - even compared to the 7-speed automatic it replaces - and enough ratios from the four planetary gearsets to cover the demands of both performance and economical driving.

The length of the upper ratios in particular is such that at motorway speeds, the ninth ratio seems to require only around 1500rpm. It's also apparent in the way that in sports mode, where the car hangs onto lower gears for longer, you have to be at quite some speed before the transmission even bothers selecting 8th gear. Another benefit of the new transmission is the efficient torque converter, that operates at 92 per cent efficiency.

What’s it like to drive?

More entertaining than you might expect, if not blessed with the same satisfying balance and interactive controls as the Porsche 718 Boxster benchmark.

The short wheelbase lays claim to some of the SLC’s fun factor, endowing it with a nimble feel that, thanks to a four-square stance and wide rubber at each corner, never feels snappy. The steering is low on feel but high on precision (though it can feel disconcertingly light at speed), and it’s easy to place the car accurately on the road. Grip at both ends feels nicely balanced too, so whether you’re driving precisely or more aggressively - turning in sharply and getting back on the throttle early - both axles give you a sense they’re sharing the workload.

If you do get on the throttle early you’ll also find plenty of traction, but even in Sport+ mode the car’s traction and stability systems are fairly eager to cut in, so you’ll need to disengage them to coerce the SLC into adopting any sort of angle from the rear.

Sport+ will be the default mode if you’re looking to have fun though. You don’t get any benefits in terms of steering feedback (only extra weight, as is typically the case these days) but the engine and transmission feel more aggressive (with a growling exhaust note that stops short of issuing the irritating bangs and pops of an A45 AMG)

It’s just a pity the 9-speed automatic can’t deliver truly swift shifts - it’s speedy enough on the way up the ‘box, but changing down with the paddles is frustratingly delayed. Other demerits include that hefty kerb weight and a lack of chassis stiffness - the former makes itself apparent in quick direction changes, with a delay between steering input and the car responding, as well as the ever-present smell of hot brakes after even moderate use, while the latter results in the cabin shimmying over rough surfaces.

Prices and rivals

The SLC 300 AMG Line starts at £39,385 on the road, with plenty of scope for adding large sums to that courtesy of the Mercedes-Benz options list. By way of comparison, you’ll pay £46,360 to get behind the wheel of the full SLC 43 AMG model.

A new Porsche 718 Boxster with the 2-litre engine starts at £41,739. In the past, the SLC vs. Boxster comparison would have been something of a no-brainer for us, but so disappointing is the new Boxster’s entry-level powertrain that it’s no longer so clear-cut.

A more closely-matched comparison might be with the Audi TTS Roadster. Also possessed of a four-cylinder powerplant, the £41,435 Audi has stronger performance than the Mercedes, an even nicer cabin (with Audi’s brilliant Virtual Cockpit display) and a precision to its handling that no previous TT offered. It’s probably the more cohesive design, too.

Specs

2.0L inline4 Engine
9-spd auto w/OD Transmission
Power 245hp @ 5,550 rpm
Torque 273Nm @ 1,300 rpm
rear-wheel Drive type
ABS and driveline Traction control
17" silver aluminum Wheels
front air conditioning, THERMATIC manual
AM/FM/HD/Satellite-prep, seek-scan Radio
2 - 1st row LCD monitor
keyfob (all doors) Remote keyless entry
rear Fog/driving lights
Heated mirrors
power Convertible top
Windshield wipers - rain sensing
MB-Tex leatherette Seat trim
driver and passenger Lumbar suppor