BMW 420i vs BMW M4

What's the difference?

The BMW 420i is a terrific car if you're after a bit of style and sophistication. Not everyone will warm to your car's nose, but if you get it de-chromed, like this white one, it really does look pretty good. It's a car that uses very little fuel, moves along smartly and is brimming with a decent amount of tech, even if it could do with a bit more safety gear at this price. 

I reckon this car is settling well into the automotive landscape and ignoring it because of a few loudmouths think the grille is too big would be a terrible waste.

Brutal, bruising and utterly brilliant, the M4 CS will be an acquired taste due to its no-compromise approach, but those willing to take the leap will find a performance car like few others at their disposal.

The internet exploded when it became clear the big kidney grille was for real. To be fair, BMW did itself absolutely no favours by ensuring the photos of the 4 Series made the twin grille look Easter Island statue sized. 

And it persisted in doing them naked, without number plates to break up the look. In the flesh, it all works, the nose is striking but not completely overblown. 

BMW coupe elegance reigns supreme in profile, however, with excellent proportions, and even in base form the wheels are the right size. The slim tail-lights and sculpted tail complete the look. It's a car I think most people love looking at. Hardly anyone mentioned the grille.

The cabin is excellent, as are all of the newer BMW interiors. It's not really a base model, given the price, but the mix of Alcantara and synthetic leather is very pleasing. 

The big screens for the media and instruments headline the cabin with high-tech style and while it's not avant-garde, it's sharp and feels premium, which is just as well.

The M4 CS is familiar in all the right ways, but definitely looks significantly jacked up compared to its lesser siblings.

Part of that is the extensive use of carbon everywhere, from its bonnet panels to its roof, front lip, side skirting and boot spoiler. But also because of its super-muscular angles and creases, including the huge dome in its bonnet.

Also exclusive to this M4 CS is the light treatment, with the front LEDs lighting up with yellow highlights the brand says are supposed to be reminiscent of GT racing cars.

At the back, the rear lights are flush with fibre optic lighting, lending a flowing and unique light signature that looks epic at night.

Inside, it's a sea of carbon, with the lightweight racing seats, the dash inserts and the centre console all lined in it. It is a perfectly finished space, though, and one that's also flecked with red, including a 12 o'clock band on the thick-rimmed steering wheel, the seat backs, the contrast stitching and the paddle shifts.

Be warned, though, it takes some acrobatics to climb into or out of the CS. The seat bottoms have these super high edges that double as grab handles, but require some awkward contortions to navigate.

In short, it looks angry, this M4 CS, inside and out.

As a sports coupe, it's hardly a practical all-rounder but it's not a squishy 2+2 either. The rear seats are sculpted for maximum headroom and have the added bonus of holding onto rear passengers. 

Six footers won't be super-comfortable but it's bearable for short trips. There are two ISOFIX points back there, too. 

The front seats electrically fold out of the way for ingress and egress, but it's not an elegant process.

Front-seat passengers score two cupholders and bottle holders in the doors and a black hole for your phone and its wireless charging pad.

The boot takes an impressive 440 litres and the rear seats split and fold like good little soldiers.

It all boils down to how you classify practicality in a car like this. I mean, the basic stuff is all there – it's got two doors, four seats and a boot capacity of 440 litres.

It measures 4801mm in length, 1918mm in width and 1399mm in height, and room for front seat riders is good, but less so for anyone you squeeze into the back. There are even ISOFIX points for a child seat.

But if you consider practicality the practical pursuit of performance, then the M4 CS has plenty of perks.

We're talking a $254,900 entry price for the M4 CS, which – despite my attempts at justification – is a lot. Remember, the regular M4 is $168,700, and the M4 Competition is $186,500, so we're talking a sizeable premium here.

BMW justifies that price increase in two ways. The first is scarcity, with the M4 CS limited to just 50 examples in Australia. And the second is by dialling up every aspect of the M4's performance to terrifying levels.

The engine outputs are up, the weight is 20kg down, there are better brakes, better seats, a louder exhaust, a stiffer chassis – it goes on and on.

We'll get to some of the performance stuff in a moment, but here's what else your money buys you with the M4 CS.

It starts outside with staggered alloys, 19-inch up front and 20-inch at the rear, wrapped in track-ready rubber. There's also hi-po 'M Compound' brakes with red calipers, lightweight carbon racing seats that are heated up front, an Alcantara-trimmed steering wheel, the 'M Carbon' exterior package with carbon bonnet and roof, adaptive 'M Suspension' and a titanium exhaust that howls like the winds of hell.

The less performance-focused stuff is similar enough to the other M4 models including a 12.3-inch centre screen with digital radio, Apple CarPlay and Android Auto, a second 14.9-inch screen that handles your driving data and a head-up display. There's also twin-zone climate control, Merino leather upholstery and ambient interior lighting.

But all of that is secondary, really. This is about performance, specifically of the brutal kind.

The 420i’s 2.0-litre turbocharged four-cylinder, codenamed B48, spins up 135kW/300Nm. Driving the rear wheels through an eight-speed ZF automatic transmission, you'll go from zip to the 100km/h mark in 7.5 seconds, which is brisk, if not staggering.

BMW has found yet more grunt lurking in its trusty 3.0-litre 'M TwinPower' six-cylinder petrol engine, with the M4 CS now pumping out 405kW and 650Nm.

That's a decent jump from the 390kW and 620Nm served up by the M4 Competition, and a giant leap from the outputs of the 'base' M4 – 353kW and 550Nm.

Predictably, then, the CS is the fastest of the lot, knocking off the run from 0-100km/h in 3.4 seconds, compared to 3.5 and 4.2 in the Competition and M4, respectively. The top speed is also dialled up to 302km/h.

All that power is channeled through an eight-speed automatic and sent to all four wheels on demand, with the help of an 'Active M Differential'.

BMW's official combined-cycle figures seem to be slowly moving towards reality. The 420i's sticker figure of 6.4L/100km was met with an indicated 6.8L/100km, which was excellent going for almost exclusively suburban and urban running. 

It's a solid result, but being a BMW, it's premium unleaded only for its 59-litre tank.

With my generally unsympathetic (but not psychopathic) right foot, that means a real-world range of over 800km between fills.

The M4 CS is fitted with a 59-litre fuel tank, which – given the BMW's official fuel claim of 10.2 litres per hundred kilometres – should deliver a driving range on a full tank of 541 kilometres.

But... BMW also says the regular M4 – you know, the one that makes 52 fewer kilowatts and 55Nm less torque – uses 10.1L/100km, so do with that information what you will.

One of the main things that sets a BMW sedan or sedan-based coupe apart is that they're good everywhere, except perhaps in quicksand. 

As the platform has matured and BMW's persistence with run-flat tyres has yielded improvements in tyre construction, the 3/4 Series platform (and many others - the internal name for the platform is CLAR) has once again become the benchmark for ride and handling.

For some people reading this, that's a lot of blah blah blah but the main point is, it's a terrific thing to drive whether you're dawdling along in traffic, dealing with traffic calming or bombing down your favourite deserted road.

The Bridgestone tyres on the 420i aren't as ultimately grippy and sticky as the alternative rubber on the 430i but they work well in town and are quiet on the 80km/h roads so prevalent in Sydney. 

The steering is absolutely lovely, providing just the right weight at any given speed and throwing in the road feel to inspire confidence.

Ride around town is compliant but with the whiff of fun if you decide to push things outside of the city. 

Its capabilities are still more than worthwhile day-to-day, however, because the way it handles the need to duck in and out of spaces in traffic is extremely handy.

The 2.0-litre four-cylinder is as smooth as rival Audi's. It doesn't sound like much (with a few vestigial pops in Sport mode) but it's certainly got the power to get you out of sticky situations and a transmission that's willing to play ball, whether in Sport or Normal.

Without the adaptive suspension of its 430i and M 440i brethren, this is a very smooth, easygoing sports coupe, with just enough sportiness to keep you interested, if you're that way inclined.

The hardest and angriest M4 of all time is, perhaps unsurprisingly, hard and angry. This is a race track specialist, but because I don't happen to own one of those, my first experience with the barking (and barking mad) M4 CS was navigating my way back from BMW's inner-city dealership.

Like it or lump it, you're going to read some Porsche comparisons here, because you're talking not too far off base 911 Carrera money, and suddenly I find the two Germans doing battle for a spot in my dream garage.

First things first, the BMW won't be much chop for daily driving for most people. Happily, I have a sickness for uncomfortable sports cars. It tells me that no compromises have been made in the pursuit of punishing performance.

A good thing, too, because the BMW, at city speeds, can be punishing. Everything feels heavy, the seats aren't overly comfortable – especially the hard bits that tend to dig in when cornering – and it stiff-arms its way over road imperfections, that exhaust booming and barking as it does.

Again, I loved it, and you probably will, too. But it's still not the kind of car I'd relish sitting in the morning peak hour rush in.

But escape the confines of the city and the BMW M4 CS suddenly makes a whole heap of sense. The acceleration is genuinely brutal, and wonderfully theatrical, with that quad-tipped titanium exhaust barking and snarling as you rocket towards 100km/h.

The steering is brilliant, with feedback fed to your wrists via that thick-rimmed wheel, and the entire experience feels sharp, super engaging and edgy.

You can push the M4 hard and fast, and I'm certain my limited talents would run out far before the BMW's would, but there's this thrilling sense of peril sparked by the aggression of the experience, that I love.

It's like the magic of a roller-coaster, I guess. Even if you know nothing is going to happen, you never really know, right? And in that lies the magic.

But back to original question, this or a Porsche 911? There's no doubt a Carrera is a better all-rounder, in terms of comfy commuting and race track fun, but this angry M4 is all shouty theatrics, all of the time.

I bloody love it.

Expect no ANCAP rating here, I'm afraid. But the BMW 4 Series does wear a five-star rating from 2019.

The M4 CS gets six airbags (driver and passenger, side airbags, head airbags), along with what BMW calls its 'Driving Assistant Professional', which bundles active cruise control (with stop and go function), front and rear cross-traffic warning, 'Steering & Lane Control' and 'Lane Keeping with Side Collision Warning'.

BMW offers a ho-hum length of three years and 100,000km of warranty coverage. Mercedes has gone to five years so one wonders why BMW (and Audi) hasn't joined its German rival.

Servicing is entirely reasonable at $1650 for a five-year/80,000km package that covers the 12 month/16,000km servicing regime. 

At $330 per service, it includes things many carmakers don't, such as brake fluid and spark plugs. 

You can go full noise with the 'Plus Package', which costs $4500 and chucks in brake pads, rotors and even windscreen-wiper replacement. That doesn't seem like terribly good value to me unless you drive like a lunatic.

The M4 CS is covered by BMW's five-year, unlimited-kilometre warranty, with condition-based servicing available in packs, which will cost you $3530 over five years/80,000km, or $2900 over four years/60,000km.