BMW G80 M3 Vs M340d: The Precision Tool Vs The All-Rounder

Earlier this year, I declared ‘my’ new BMW M340d Touring as “the best new car on sale”. I still stand by that statement - it really is the ultimate all-rounder. It’s stealthy, quick, efficient and swallows big mileage like it’s nothing. And having spent much of the last two months behind the wheel of our Skoda Octavia vRS crew car for towing duties, it’s abundantly clear why the BMW costs nearly £25,000 more at £62,000. But that’s a discussion for another time.

What I want to do now focus on the differences and similarities between the M340d and its big, petrol-powered brother, the G80 M3. This wasn’t some big, in-depth twin test we set out to do - it just so happened that we had these two cars together at Curborough for a video shoot, prompting me to have a ponder, particularly as the M340d is so damn quick. Does anyone really need an M3 when this diesel rocketship exists? Well, yes. Let’s get into why.

The biggest difference between the two is how much heavier the M340d feels, despite it not being much more lardy on paper. There are a few reasons for this. There’s the use of a diesel engine rather than a more responsive petrol unit, the presence of all-wheel drive, softer suspension, big leather seats, and that estate body (there is, however, an M3 Touring inbound, and an all-wheel drive one).

Getting back in the M3, it almost feels half the weight thanks to its fast, pin-sharp handling, and those carbon seats that grip you tightly as the lateral G figure rises. The M3 is also far more exciting to drive at any speed and makes you feel totally at home behind the wheel. The M340d is less of a car you become part of like the M3, it’s more of a car you learn to rely on. The M340d is still special, but because its remit is more ‘best friend’ than ‘mistress’, you relax into steady progress rather than punch the throttle for thrills.

That said, the way the M340d launches isn’t a million miles off the M3 because it’s the fastest accelerating diesel car you can buy. With all-wheel drive, 345bhp and 512lb ft, 0-62mph takes only 4.6 seconds, which is a mere 0.7sec slower than the M3. In-gear acceleration is also pretty savage thanks to that torque output, which is actually a little higher than the M3’s - it manages ‘only’ 445lb ft. Pfft.

One final thing that separates these cars is the way they brake. The M3 comes to a controlled, almost eye-watering halt, while the M340d by comparison labours and dives more to stop its mass.

Ultimately, the M3 is the one to have for posing, lap times and bragging rights, but out on the road, the M340d will get you further and to your destination more quickly, particularly if it’s a little damp out. It’s also something of an automotive Moses, since wherever you go the seas of cars parts in front of you. Why? Because everyone seems to think it’s an undercover cop car.

So, if you want a car to be fast on track, pick the M3. If you want a car to be faster everywhere else, the M340d is the one to go for.