One key question to answer about the new M3 Competition xDrive: driven back to back, can you tell any difference between it and the standard rear-drive M3?

Handily we currently have a long-term regular rear-drive M3 being run by Rowan Horncastle. Time for a get together.

Firstly, a quick recap. Both use an identical 3.0-litre twin turbo straight six with over 500hp, and team that with a standard fit 8spd automatic gearbox.

There’s no twin clutch transmission or hybrid jazziness in there anywhere.

If you want that, wait for the new Merc-AMG C63, due next year. Which will also, we believe, use a switchable 4WD system as standard.

This is the first ever 4WD M3, the first time Audi’s RS4 has ever had a nose-on showroom rival.

Think of the BMWs xDrive 4WD system as an option you fit to the car rather than a separate model.

And no, I still haven’t quite got over how expensive a new M3 is. I can’t help thinking that the reason we’re not seeing many of these around at the moment has less to do with the nostrils and more to do with the hefty repayments.

I digress. It’s a clever bit of kit, rear-drive only until the rears run out of ideas and fire a bit of power forwards via a multi-plate clutch.

It’s always been a smooth, well integrated system, BMW’s xDrive, and only adds 50kg to the car’s weight, albeit mostly over the nose (new driveshafts and centre diff etc). It obviously shares both tech and general demeanour with the current M5.

So we drove them back to back down and around Salisbury Plain (green is RWD, purple is 4WD).

No difference in the jaunty everyday tuck ‘n’ grind. I thought there was a fraction more heft to the 4WD one turning into roundabouts, but probably only because I was looking for it.

Both are pretty unforgiving in urban areas – the ride is solid and uninterested until it’s got something to get its teeth into. Flatten the throttle at a national speed limit sign and it’s highly unlikely the rear drive car will do anything other than squat and roar off.

As we’ve said before, the M3 does not lack traction or grip. The cornering speeds are dizzying before you’ve even got to the point you might be feeling what the 4WD is up to.

The electronically controlled rear diff in this new M3 is, if you geek out on these things, perhaps the most impressive thing about it.

The precision with which you can dole the power out, the sense you get of which wheel it’s going to and the smooth interventions of the stability control if you do over do it, I reckon give you more feedback than the slightly numb steering.

That’s all still there with the 4WD version. Because I don’t know at what point the rear axle decides it’s had enough, but it likes a challenge.

There’s a reluctance to hand power forwards which really appeals to me. And that’s before you even start playing with the modes.

Standard 4WD is very neutral. You might get a fraction of slip at the back, but before you notice the fronts are working seamlessly and you’re pointing exactly where you were hoping. This is the mode you’ll be in 99 per cent of the time.

Because to get to 4WD Sport you have to disable the DSC stability control. Which seems daft to me. This is very much rear-drive.

You will get proper slip angles and sweaty palms, but a better chance of saving yourself because the fronts – you’ll discover mid-slide – are also doing some work.

Then there’s 2WD. Full brave pants. I don’t really know why you’d bother unless you’ve turned up at a ‘Learn To Drift’ event and decided you’d rather not use that ratty 180SX they had ear-marked for you.

The thing is you can’t have the ‘purity’ of rear-drive with the security of stability control. Which you can with the standard car.

However, the inverted commas were for a reason. As I said earlier the G80 M3 has so much grip and holds on to it so rigidly that this is not a feel and finesse machine.

4WD suits it. If it were me, I’d spec it. And it did feel notably different. I reckon this is probably down to the tyres and a bit of mechanical bedding in, but the 1600-km-from-new 4WD car was snappier at the limit than Rowan’s 20,000-km rear-drive car wearing half-worn Michelin Pilot Sport 4Ss.

The 2WD might have had a little less bite, but it flowed better, the diff was calmer, more progressive – which actually made it harder to get some slip angle into.

So there you go, the new M3 xDrive is more oversteer-ready than the rear-drive version. You heard it here first.

And hopefully you realise how pointless it all is anyway. Have xDrive, not because it’s lairy but because it suits this new M3 better.

Fit winter tyres – 4WD will manage the extra squidge better and on those solitary snow days that grace our winters perhaps once a year you’ll be ever so smug.

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