What are you driving?

Until the full-fat BMW X5 M comes along, this M50d is the most potent version of the fourth-generation X5 SUV that you can get in Ireland. It uses a quad turbo 3.0-litre in-line six-cylinder diesel engine that churns out a phenomenal 760Nm of torque. That's the same engine as you'll find the larger X7, and there's no difference in power outputs between them, only marginal differences in combined fuel consumption figures.

Being an M Performance Vehicle, the X5 M50d gets some identifying features that separate it from the common-or-garden X5. The large kidney grilles, door mirrors and design accents on the bumpers are finished in Cerium Grey that is specific to this model. BMW also applies that same colour to the wheels. The fact that those wheels, which are 22-inch items, don't look out of place, gives you a sense as to the true size and presence that this fourth generation X5 has.

Name its best bits

As large as the X5 M50d is, it does a good job of disguising it. Looks are, of course, subjective, but the overall design of the X5 works, with enough curves in the right places to hide some of that bulk. It's still instantly recognisable as a BMW X5, and it's arguably the best-looking generation since the first. Being the M50d, it gets some additional styling cues that go in its favour, but even so, it's a design that has lots of appeal.

It isn't just about turning heads, as out on the road the X5 handles quite well. Fast direction changes are managed well, and the electrically assisted steering has a consistent feel to it.

A significant part of the driving experience in this X5 is down to that engine. It's quite an impressive thing that produces more than enough power to propel it along with real ease. Up at motorway cruising speeds and with the transmission running in top gear, the engine purrs along nicely, at times not much above idle. As impressively as the more popular X5 xDrive30d insulates the diesel noise, here it has a more purposeful rumble to it. For a diesel engine, it does have a more free-revving characteristic to it, but almost all of its performance is in the lower portion of the rev range, so pulling on the upshift paddle sooner will help keep you in that tsunami of torque.

On a more practical note, the split tailgate has its uses, and it's nice to be able to open the top section to throw in smaller items. That said, the extra length that the bottom section adds when lowered can make it a bit trickier to reach things that are further inside.

Anything that bugs you?

The fact that the current BMW X3 is longer and wider than the first generation X5 tells you all you need to know about how much the X5 has grown in size. Yes, it's far safer and more luxurious, but on some Irish roads you do feel every bit of its two-metre width.

And while there's a lot to like about the X5's design, some of the optional features are more questionable. Namely the 'CraftedClarity' crystal glass effect on the gear selector and iDrive rotary controller. It just looks cheap and tacky, more like something from the jewellery section of the Argos catalogue than BMW's best design department.

And why have you given it this rating?

We often refer to large SUVs as feeling like tanks, but it's apt in this case. The X5 is already a serious piece of kit, and adding this engine to it makes it all the more impressive. It's probably overkill for most people, but if you're looking for a rapid SUV and you're still keen on diesel, then this is one to try.

What do the rest of the team think?

While the sledgehammer hit of the M50d's engine is, to say the very least, gloriously addictive, I'm not sure it's strictly necessary. The standard 30d engine has more than sufficient poke, and the wall of torque of the M50d unit can actually make the X5 feel a touch wayward and twitchy at times when you're pressing on. Not necessarily what you'd want with a car this big... Still good fun, mind, if you have the cash.

Neil Briscoe - Editor-at-Large

I have to agree with Neil in that the X5 xDrive30d is the pick of the range and nobody really needs the M50d's extra go.

Shane O' Donoghue - Editor