When BMW told us its new BMW X5 M was available for review, our curiosity was quick to the draw, it’s not every day that you get to swap your used 2-speed and test-drive a car worth well over six figures. With the most powerful engine ever fitted by BMW into a road car (a twin-turbo 4.4 liter V8 developing 575 horsepower), the X5 M is the world’s fastest SUV. Period. So we asked to review the X5 M, if only to see if this overpowered mutant had any practical applications in a fitness lifestyle.

Of course, since it looks like an SUV and not a Ferrari, the BMW X5 M is technically a family car. Outwardly it looks mostly like a standard BMW X5, the only giveaways to its wolf-in-sheep’s clothing nature being the massive 21-inch tires and the little M class badges here and there.

Drive the X5 M in the city, and it’s an eerily civilized car despite having a slow-burn hydrogen bomb under the hood. It will do a perfectly good job inching forward patiently in the drop-off line at school, or coping with the work commute. Its generous trunk means you could take your entire home gym to your next training session if you felt like it. In fact, the X5 M is so docile and practical we’d even recommend it as a great soccer mom’s car if it wasn’t for the price tag.

The reason to get an X5 M is that it will handle some situations on the road better than other cars. When you run into the following scenarios, the X5 M gives you peace of mind.

For instance, you might be driving along minding your own business when you’re flagged down and asked for help by an ambulance crew whose ambulance has broken down. You quickly transfer the heart-attack victim to the BMW X5 M and with a borrowed siren you take the patient to the emergency room in the nick of time, thanks to that powerful V8.

Or you come across a police chase in which the bad guy is driving a Porsche 911 and the policemen’s Dodge Charger Pursuit simply can’t keep up. With the authorities’ permission, you chase down the 911 through city streets and make a citizen’s arrest (yes, going from zero to 60 miles per hour in 4 seconds, the X5 M will outrace a 911).

Or when you’re shooting a TV commercial and find that the location is 750 miles from the nearest major airport and you have 24 hours to get there, but there are no charter flights. Worse, recent heavy rains have made some of the roads impassable, ruling out a rental 4WD. You’re not stressed, because you know that a BMW X5 M will get you there faster than any other car.

Okay, while the ambulance and police chase scenarios might not happen very often, I was faced with the desert shoot problem while on location in Australia. We had to get from Sydney to a TV shoot in the Australian desert, 750 miles away in the Australia outback, near a silver-mining town called Broken Hill. With no planes available to fly there, a BMX X5 M was the only solution.

So at around 4pm on a Friday afternoon, we rolled the BMW X5 M out of the Sydney garage, made an Instagram post, and immediately headed down the federal highway towards Broken Hill, hoping to get there by 12 noon the following day. We calculated we’d need an eight-hour break in the drive to allow for sleep and food, which gave us 13 hours to cover the 750 miles. That also resulted in an average speed that was safely under Australia’s highway speed limits.

On public roads, the X5 M’s truly gigantic reserves of power are simply irrelevant once you set the cruise control to follow the speed limits. But the excellent view from the high driving position, the fantastic Bang & Olufsen surround-sound system and easy climbing of hills along the way meant the drive would be effortless. And it was, until we realized a couple of hours after leaving our overnight stop in the small Australian town of Temora that the BMW GPS system was sending us to Broken Hill via the straightest route possible, taking us off the highways and onto rough country roads.

Recent and very heavy, unseasonal rains meant we were heading into vast areas of recently flooded farmland on the edge of the Australian outback. But had we backtracked to a highway we would have lost so much time we wouldn’t have made it to the shoot by early afternoon. Instead we plowed ahead (literally) and prayed that the car’s off-road ability was real and would get us there safely and on time.

We’re glad we did, because on an endless stretch of treeless farming land and salt flats we saw the beast at its finest. An ordinary car would not have got far on those hypnotically straight muddy farmers’ tracks. A big 4WD truck would’ve handled it easily but at a lumbering pace. Instead, with its massive tires, sophisticated all-wheel drive system and dynamic performance and damper controls (which do everything from maximizing traction to delivering optimum power to different wheels), the Bimmer ate up the ruts, mud and pools of water with ridiculous ease.

Farmers chugging along in their pick up trucks did double takes as one of Munich’s finest pieces of engineering suddenly grew large in their rear view mirrors in the middle of nowhere, like a red spaceship materializing out of a wormhole and disappearing just as quickly.

It wasn’t the BMW’s fault we eventually made it to the shoot in Broken Hill four hours late. We’d simply underestimated the impact of detour after detour as we negotiated the wet plains. Disagreements on the fastest short-cuts between GPS and mapping systems didn’t help (not that we didn’t trust the BMW GPS, we just wanted a second and third opinion).

But despite the marathon drive, when we got to the shoot we felt surprisingly fresh and went straight to work on the fitness shoot. On the drive back, we took the slower, highway-only route, and the car didn’t seem to mind it.

So do you really need the world’s fastest SUV? Not really. We can’t think of one practical reason you need one. But if you want that wonderfully satisfying feeling that you’re driving a supercar masquerading as a family transport, then the X5 M is worth every cent.