Long-term report: Our 420i test car meets its bigger brother, the M4 Competition

There was a time, not too long ago, where if you wanted a coupe-shaped M3, you’d buy the coupe version of, well, the M3.

However, with the last generation model, BMW split the 3 Series in two, making it only available as a saloon and estate. If you wanted it as a coupe, you now had to buy a 4 Series.

As such, this gave birth to the M4, the coupe version of the M3, BMW’s world-renowned super saloon.

Why the history lesson? Because we’ve been testing the latest-generation 4 Series for the past few months and have enjoyed our time with the car – even if most of it has been spent in a national lockdown, limiting our ability to really get to know it.

In the world of the 4 Series, ours is an ‘entry-level’ model, but as you’d expect from a car that starts at around £40,000, it doesn’t exactly feel that way That’s because the range starts with the M Sport trim, so gets 18-inch alloy wheels, leather upholstery and excellent smartphone connectivity from the off.

With the new M4 Competition booked in for a feature, we thought it would be interesting to compare the two. This is, after all, the bottom of the range versus the top.

When the M4 rolled off the back of the delivery truck, there was one obvious difference: the colour. While our long-term test car is white with black trim, the M4 is Sao Paulo Yellow. It looks like it crashed into a highlighter factory.

Now I tend to prefer my cars with more subtle shades, but some exotic models can pull off fluorescent, lairy colours. To my eyes, the M4 doesn’t quite have the obnoxious styling required to pull off such a shade, and I felt quite self-conscious behind the wheel…

That being said, the styling details for this high-performance version are lovely. This test car had a £6,750 carbon-fibre pack that added carbon bucket seats as well as exterior trim pieces. They gave off a real racey appearance and their black colour juxtaposed brilliantly with the paint.

Although the M4 might not have the Lamborghini-esque lairiness required to pull off the paint job, sat next to the 420i it certainly looked aggressive. In fact, on the face of it the changes between the two models are (relatively) subtle, as it doesn’t have large stick-on aerodynamic devices all over the car as with some performance cars, but our long-termer certainly looked much more sleek and soft in comparison.

That’s particularly noticeable at the front, where the controversial ‘bunny teeth’ grille is even more prominent on the M car. I specifically chose a white car with black grille for our long-termer to make the contrast more obvious and really test the design; it’s never really bothered me and my time with the car has made me grow to genuinely like how it looks.

The M4 pushes that a bit, though. While the standard 4 Series grille blends into the bumper a little more, the M version has no trim around the edge, instead having an almost wedge-like section of bodywork. Still, though, it looks great, and as is the case with the regular car, everyone who sees it says how it actually looks quite good in real life.

On the inside it’s a similar story – almost identical but just different enough to be noticeable. The most obvious change is the carbon bucket seats. The stiff thigh bolsters make getting in and out tricky, but once you’re in they’re fantastically comfortable.

It’s also rare to have carbon bucket seats with heating and full electronic adjustment, which might explain why they’re so pricey.

Sitting in my long-termer afterwards made the seats feel a little flat and unsupportive in comparison. On the subject of the 420i’s seats, though, they have been my only real complaint in my time with the car. I get discomfort in my lower back on longer journeys and pins and needles in my left leg, which isn’t normal for me.

Other differences were more subtle. The steering wheel felt chunkier and didn’t seem to go as low as it does in the regular car, though that might have been something to do with my seating position being slightly different in a new seat.

The last change is psychological. In my 420i, it feels small and sleek, like the car shrinks around me, but in the M4 it felt much bigger and more muscular on the road. That’s likely simply down to seeing the M body kit as you get in, then hearing the thrum of the engine when it comes on.

Oh, and then there’s the performance. The M4’s engine is a beast, and by far the most obvious change – unsurprising, considering that at 503bhp, the 3.0-litre straight-six has well over twice the power of the 420i’s 181bhp 2.0-litre unit.

Ultimately, comparing the two is a fun if pointless exercise. They’re completely different beasts, with one focusing on calming comfort and the other a no-compromises performance car. But it was interesting to see where the differences lie, and how the character of the car can alter how you feel behind the wheel.

Importantly, getting back in my long-termer wasn’t a disappointment. In general driving there’s no real difference except for the fact mine uses much less fuel. I do miss that brawny engine, but finding time and space to make the most of it is so rare that not having it isn’t as disappointing as you’d think.

Yes, I think I appreciate my ‘entry-level’ 4 Series even more now. I wouldn’t mind those £6k bucket seats, though…