Can you believe the Porsche Boxster is 20 years old? We barely can either. But back when the Spice Girls were miming Wannabe on Top of the Pops and kids were losing their minds over POGs, the Boxster was waiting in the wings, preparing itself to utterly dominate the sports car market.

Today, the mid-engined two-seater is widely regarded as the benchmark roadster, a car that all other cars want to be. But it's all change two decades in: the new-generation Boxster comes with a new name (that's the 718 bit), revised styling and - brace yourselves - a choice of either a 2.0-litre or 2.5-litre four-cylinder boxer engine. Yep, Porsche has done away with the flat-six of old.

When we drove the 718 Boxster at its launch in Spain last year we summed up our experience by saying "a large question mark hangs over the new range of engines... it may seem like a minor point but for some they will almost certainly tarnish the experience."

After a full week and several hundred miles driving one in Blighty we bring our verdict on whether such concerns become the dominant factor, or melt away into the background of an otherwise fantastic car.

For those not fully up to speed on this engine issue, first an explanation. The world is on a mission to reduce CO2 output resulting from transport. Car makers have to get their fleet average emissions down, across all markets, in coming years.

Pocket-lintPorsche 718 Boxster S-9 copy

In response, Porsche has gone on a turbocharging and downsizing spree - the best way to improve fuel consumption (at least in official tests) and deliver the same or more power than before. Hence normal 911s now sport turbos (read our review here).

But when it came to the Boxster and Cayman refresh - now dubbed 718 in reference to Porsche's 50s and 60s racercars - Porsche went nuclear. Not only did it stick turbo-chargers on the engines of the Boxster and its hard-top twin, the Cayman, it downsized the engine's cubic capacity and cylinder count, too. The old, six-cylinder 2.7-litre of the standard car and 3.4-litre of the S models, are replaced with four cylinder engines, of 2.0 and 2.5-litre capacity respectively. Momentarily, it's rumoured, hell froze over.

Look at the naked figures and you can see the benefit. Official combined fuel consumption for this 2.5-litre S model jumps from 31mpg to 34.9mpg. CO2 drops from 211g/km to 184g/km (or 167g/km with the PDK automatic). At the same time, power jumps from 310bhp to 350bhp and there's a massive slug more torque. As a result 0-60mph now comes up in 4.6-seconds (4.2 for the PDK with launch control). The Boxster S is no longer at risk of having its trousers pulled down by a hot hatch and these figures are hugely impressive. On paper…

So what's the problem? There are two: noise and delivery. If you've ever driven a Subaru (funnily enough, they use flat-four engines like Porsche has done here) then you'll recognise the sound as you stick the key in, twist and hear the engine quickly spin into life. The Porsche 718's engine catches with a woof and settles to a busy, zizzy idle that's slightly irregular sounding. There's an underlying percussion of an unusual beat. It sounds thinner, reedy and less cultured than the old flat-sixes.

Pocket-lintPorsche 718 Boxster S-18 copy

Those old engines, over a rev-range which arced to nearly 8,000rpm, used to envelop you in all range of sounds - a baritone, deep blare in the middle of the rev range, crescendo-ing to a spine-tingling wail as you chased through the last few rpm. The new engine? It just blares, in a monotone noise, right throughout the range. There's no discernible change in tone, or character as the revs rise and fall.  

Our test car's sports exhaust tried hard with pops and bangs when coming down the gears or when lifting off the throttle suddenly during a burst of acceleration. But it sounds choreographed. A bit one-dimensional. On the motorway, the engine just drones on, slightly spoiling one of the 718 Boxster's best kept secrets: its in-cruise refinement and ability to cover long distances without wearing you out.

Less of a problem to some will be the way the engine delivers its power. It's an exaggeration to say the Boxster S delivers its power like a turbo-diesel, but this engine does feel very turbocharged - flat below 2,000rpm, then waking up in a rage, like a 4am Donald Trump tweet storm.

Between 2,000 and 5,000rpm, in pretty much any gear, bury your right foot and the 718 devours the ground in front of it. This is a seriously fast car now - it no longer feels like the power has been deliberately held back to make you buy a 911.

Pocket-lintPorsche 718 Boxster S-31 copy

That's in stark contrast to the old car, where occasionally the engine's need for revs could catch you out in the wrong gear - it was just getting going above 5,000 rpm - whereas in the new car, above 5,500rpm and the engine starts to feel slightly strained. It doesn't run out of puff, but there is little point now in chasing those last few revs before the red line.

If you're buying a 718 for pottering, cruising or boulevard showing off, if you're one of the people who'll never rev their sports car over 5,000rpm, if you're jumping into a 718 Boxster as your first sports car from something like a turbo-charged hot hatch then this engine will suit you better than the old one.

But if you're one of the Porsche aficionados who has lived for the old flat-six noise, loved to have to work the engine hard and got a kick out of an engine that's linear and thrives at its upper end, this new four-cylinder motor is likely to feel like fake progress.

Beyond the engine the 718 Boxster S is one of the sports car greats. It manages the difficult feat of being brilliantly easy to live with - that's true more so than ever before - yet to drive it within an inch of its life, on a good road, is to attain driving nirvana.

Porsche has changed every panel except the roof, bonnet and bootlid to transform 981 Boxster into the 718 Boxster. But this is a Porsche-update - so it looks little different initially. The new wheels, colours, clear lamps and flashy details help the 718 standout like it never has. But showy has never really been a Boxster thing. We liked the vibrant yellow of our first drive S model in Spain, prefer the demure red-roof on silver body of our review test car, while others will get kicks out of Miami blue and black wheels car.

Pocket-lintPorsche 718 Boxster S-10 copy

The full-on red interior, we're less sure about. Beyond the colour way, however, the interior is where Porsche has rung the biggest changes. In the tech specs, the 718 Boxster follows the 911 with a new capacitive, glass-fronted touchscreen, digital display and steering-wheel mounted mode selector.

All of which mark a notable improvement over their predecessors. The screen's fast, graphically better, gives you Google Earth views and the mode selector wheel allows for easy flicking between normal, sport and sport+ modes. Beware though, Porsche still charge you £1,052 for sat nav, £284 for DAB radio and £801 for Connect Plus (connected services, CarPlay activation). Some things never change.

Storage space could be better too. The centre tunnel storage bin is smartphone-holding thin, there's no longer a shelf slot under the hood fold - but the Boxster counters by being the most practical of all sports cars, with its two boots able to hold enough space for a couple on a two-week tour.

Pocket-lintPorsche 718 Boxster S-35 copy

The stuff the Boxster has always done well is still here. It's refined and comfortable with the top down, which you can raise and drop on the move up to about 40mph without losing your toupé.

We've saved the best part of the Boxster until last, because where it still wins out is in the driving dynamics stakes. This car steers, turns, rides, lows and stops better than almost anything on the road. There are many people who irrationally hate Porsches. We suspect none of them have driven a Boxster on a quiet country road.

Pocket-lintPorsche 718 Boxster S copy

It's possible to feel a meld between you and the car as a machine, that is like little else. The clutch isn't so much heavy as meaty - it feels like you're actually moving a piece of machinery rather than floppy elastic as on many modern cars.

The steering is improved thanks to the faster, better-weighted rack of the 911 turbo being fitted. And the car goes round corners like it always has - with seemingly endless grip, perfectly balanced and pivoting around the driver.

The brakes are stunning too. They retain that Porsche thing of not being over-servoed, so at first it feels like you have to press the pedal a scarily long way to really stop quickly. And then you realise it's setup like this because it's easier to modulate small inputs and better for braking and blipping the throttle with your heel.

The manual gearbox is a delight to use - although it's a pity you can't turn the rev matching function off in sport and sport+ modes. And on 19-inch wheels the Boxster rides beautifully over battle-scarred UK tarmac.

Pocket-lintPorsche 718 Boxster S-14 copy

Its chopped-off roof seemingly makes little difference to the body structure – although drive its Cayman brother and you will notice the difference in stiffness. Notably, our car came with optional Sport Chrono pack (£1,125), Porsche Active Suspension Management (£971), and Porsche Torque Vectoring with a mechanical differential (£890). It's hard to assess their true worth without a comparative car, but if you're getting big wheels we'd recommend the suspension management. And the mechanical differential can certainly be felt when you're really pushing on it - in a good way.

Verdict

On our last wintry Sunday night with the Boxster it was about 7C outside. It had just stopped raining, the roof was down and the North Yorkshire moors were emptying of the snail-pace day trippers. The crisp purple edge illumination of the LED headlights (£1,344) picked out the road ahead with definition that gave confidence to really press on, and we were reminded just what a brilliant, enjoyable sports car the 718 Boxster still is, in spite of its droning new engine. Driving like this with the roof down, our one wish was that there was still a howling flat six behind our heads.

You can't ignore that propulsion device behind your head. In the 718 Boxster, its location makes it such a core part of the experience that to pretend it's not an issue would be to dodge the critical question here. You end up feeling sorry for Porsche - its engineers are deeply proud of this engine and the power and economy they've got it to deliver. But even they'll admit they tried to work with the flat-sixes, yet the smaller bodyshell of the 718 cars means they just don't fit with all the turbo ancillaries attached, whereas they do in a 911. This four-cylinder, turbo-charged route, was the only way.

On paper, everything the 718 Boxster does is better than its predecessor. It would make a terrific car to have on your drive - easy to drive, a doddle in traffic, surprisingly practical and able to deliver that thrilling drive when you want it - but in this market, a car's emotional appeal has importance above its rational, on-paper specs. And the new car has lost some of its soul - particularly compared with the previous 981 Boxster S.

We yearned to own a 981. We still miss our 987. The 718 doesn't hold the same place in our affections. It's easy to argue this is still the best car in its class. But whereas before we would have recommended a Boxster without exception, now we'd suggest that if you're in the market for a car like this, you should at least take a comparative drive in the competition - cars like the BMW M2, Jaguar F-Type, and Audi TT RS.

Talk about the 718 Boxster S without mentioning the engine and the ingredients are that of a no excuses, 5-star car. As it stands, however, that new engine progress feels like fake progress.