There are all sorts of reasons to buy a new car. You need something reliable for commuting to work. You've got a family to schlep around. You need to haul plywood, or tow your boat to the lake. All of these are great reasons to consider something like a Jeep Grand Cherokee.

But this 707-horsepower Trackhawk? You buy that one because you can.

Jeep meets Hellcat

The 2019 Jeep Grand Cherokee is offered in a dozen or so different models, including an already-fast SRT variant. You'll be able to tell a Trackhawk from lesser Grand Cherokees thanks to its bulgy body work, yellow brake calipers and quad exhaust outlets at the rear. Up front, you'll find cooling intakes where the SRT model's foglights usually live.

The Trackhawk is the range-topping Grand Cherokee, with a 6.2-liter, supercharged V8 engine -- the same one you'll find in the Dodge Charger and Challenger Hellcats. 707 horsepower is complemented by 645 pound-feet of torque, and combined with an 8-speed automatic transmission, scoots this 5,300-plus-pound, all-wheel-drive SUV to 60 miles per hour in just 3.5 seconds, on its way to a top speed of 180 mph.

The Jeep Grand Cherokee Trackhawk is the quickest gas-powered SUV you can buy today. Sure, a Tesla Model X is a little bit quicker in its most powerful trim, but electric cars aren't for everyone. And falcon doors are silly.

While the Trackhawk will happily toddle along like any other five-passenger SUV, it's at its best when you're digging deep into the throttle. Smash the gas and the Jeep hunkers down on its haunches, the transmission kicks down and you blast forward like you're entering a wormhole into another dimension. You can hear the supercharger's high-pitched wine, accompanied by the glorious rumble of that big V8. The only thing louder is my maniacal laughter.

Happily, the Trackhawk isn't just a straight-line star. On great backroads, third gear keeps the engine on boil, right in the heart of its torque band between 3,500 and 5,500 rpm. Easy on the brakes, and the Jeep settles nicely into a turn, where a heavy steering wheel communicates what's happening where the tires meet the road.

Huge Brembo brakes provide incredible stopping power, with 16-inch rotors with 6-piston calipers up front, as well as 14-inch rotors with four-piston calipers out back. There's solid pedal feel with a predictable bite point, but slam on the stoppers and the Jeep's rear end can get a bit squirrely, even in a straight line.

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The Jeep's Sport mode is best suited for this kind of driving, with its stiffer suspension settings and reprogrammed shift mapping. There's a Track mode, if you're up for it, but it makes the ride quality a bit too harsh for public roads. Auto, Snow and Tow modes are also on offer, for daily driving scenarios, bad weather or when you need to put the Grand Cherokee to work.

Other high-performance SUVs like the Porsche Cayenne Turbo and BMW X5 M are a bit more graceful, but they're also a lot more expensive. The Jeep can't handle twisty roads with the same kid of finesse, but it'll still entertain you every day.

Just remember, all that high-horsepower goodness comes at a huge fuel expense. The EPA rates the Grand Cherokee Trackhawk at 11 miles per gallon city, 17 mpg highway and 13 mpg combined, but exploit all that power at every green light like I did and you'll see poor numbers. My average after a week? Just 10.6 mpg.

And while the Jeep name is synonymous with off-road credibility, that's not what this Grand Cherokee is for. With 20-inch wheels shod in 295/45-series Pirelli P Zero tires, this thing is made for asphalt only.

Nice-ish, spacious-ish

The Trackhawk's interior is comfortable, but far from truly luxurious. My tester has the full, over-the-top red leather scheme, which appeals to my more-is-more aesthetic. Material quality is fine, mostly, but not great -- and certainly not as good as what you'll get in the Jeep's pricier rivals.

Rear passengers have adequate space, and in fact, the Jeep boasts more headroom than a 2018 BMW X5 M. Cargo capacity behind the second row is also only average, with 36.3 cubic feet of space on offer. Fold the seats down and you'll get 68.3 cubic feet, which is smaller than what's offered in the Mercedes-AMG GLE63 (76.7) and the aforementioned X5 M (80.3).

Tons of standard tech

Onboard tech is in high supply, with an 8.4-inch Uconnect touchscreen infotainment system standard, complete with Apple CarPlay, Android Auto and a 4G LTE Wi-Fi hotspot. The Trackhawk's instance of Uconnect also gets performance pages, where I can monitor g-forces and performance data, and set up parameters for the launch control. Two USB ports up front are joined by two more for back-seat passengers, and there's a 12-volt outlet in the center console for powering other devices.

Driver's aids are plentiful, standard and customizable. Lane-keeping assist can be set to early, medium or late intervention, and the steering assist has the same three settings, as well. Similarly, blind-spot monitoring can be set to give an audio or visual warning, or both. You'll probably want to just keep it on the visual setting, as the aural alert is pretty loud.

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Adaptive cruise control is standard and can bring the big Trackhawk to a complete stop and pause for a few seconds. After a simple tap of the gas or click of the "resume" button, the Jeep gets up and going again.

How I'd spec it

The 2019 Grand Cherokee Trackhawk starts at $86,650, but can quickly climb to a six-figure price tag. The tester you see here comes in just a few hundred bucks under that lofty $100,000 mark. That's a lot of money, to be sure.

I'd try to keep the price down a bit by deleting the $2,095 panoramic sunroof. It's expensive, and I don't really need it. The red leather is nice, but it's also a lot of money -- $4,995 -- and forces me to add a $2,095 audio system, as well. Pass.

Instead, I'll just get the $995 towing package. Since the Trackhawk is rated to tow 7,200 pounds, that's makes it pretty capable for hauling. I'll also add $895 for sticky, three-season tires. This keeps my dream Grand Cherokee Trackhawk at $90,035, including $1,495 for destination.

Irrational and awesome

It's tough to find an SUV that's this bonkers at a less expensive price point. The BMW X5 M costs over $100,000 right from the get-go, and add another $8,000 or so to that if you want a Mercedes-AMG GLE63. A Range Rover Sport SVR is another great option, but again, you're looking at $113,900 to start.

Perhaps the strongest argument against a Trackhawk is the already-wonderful Grand Cherokee SRT. With 475 horsepower, it's still plenty fast, and starts at $68,145 -- a full $18,505 less than the Trackhawk.

Really, the Grand Cherokee Trackhawk is the answer to a question nobody asked. It's over-the-top, loud, brash and totally unnecessary. But that's also exactly why I love it.