The Mercedes GL 63 has been infused with a significant dash of performance in its new AMG avatar

AMG, Mercedes-Benz' in-house performance sub-brand, works to inject the company's models with sportscar-rivalling power. And it's been doing this for years. Now while that may sound impressive, AMG has pulled off a true feat by adding a massive dose of power to the mammoth GL-class SUV.

On paper, the GL 63 AMG looks as menacing as it does in the metal. It weighs in at a huge 2580kg and that’s after Merc has replaced the heavier four-wheel-drive system with a lighter one on this model. Of course, getting 2.6 tonnes moving is not the issue, but to give it blistering performance is. This is where AMG’s M197 twin-turbo V8 – basically the same as used by the E63 AMG – comes in. Seriously potent, incredibly high-tech and very adaptable, this motor powers all AMG cars. Here it’s tuned to deliver a serious 550bhp and even more torque. What’s a bit more important, however, is that the 77.5kgm of torque comes in from as low engine speeds as 2000rpm. Just perfect for something this heavy.

While the spec sheet does seem impressive, I still find it hard to believe AMG has managed to enthuse this gargantuan GL with sprightly performance. After all, in the flesh, it dwarfs everything from Safaris to XUV500s.

It's hard to tell the difference from a regular GL at first glance. There is that A-shaped inlet under the traditional grille, for extra cooling, which is quite difficult to spot. And the 21-inch wheels look only slightly larger than those on the regular car. The easiest way, by far, is to take a look at the rear, where four exhaust pipes in chrome stick out.

It's time now to witness the AMG experience first-hand and we head out in the direction of the Mumbai-Pune expressway, where the GL 63 AMG will have a bit more room to expand its performance envelope.

On the inside, it doesn't feel too different from the standard car. Acres of space for seven passengers and at the same time, surprisingly manageable from behind the wheel as well. It takes a little bit of time to get used to, but once you do, it's quite comfortable. The shove provided by the motor, even from low speeds, makes overtaking manoeuvres in traffic very easy.

While the massive weight is very capably handled from low engine speeds, as you squeeze the accelerator hard, there's a huge surge of power past the 3500rpm mark. The GL rocks back gently on its rear wheels and leaps forward with an intensity that defies belief.

As we hit the expressway, some empty stretches of road open out and it's time to unleash AMG’s rumbling, snorting, fire-spitting physics experiment on wheels. I select the Sport+ driving mode and stomp on the throttle. And it simply eats up concrete at an unbelievable pace.

If you don’t pay attention, this massive SUV has the ability to take you to the wrong side of 200kph before you think it has got to 160.

How quick is it? The 0-100 comes up in just over five seconds, and by the time 18 seconds have elapsed, it’s almost at 200kph. What’s also impressive is that stability around long corners is fantastic. The long wheelbase, wide stance and wide 300-section tyres give it masses of grip, and there’s almost no flip-flop or shifting around, even at really high speeds. And this doesn't really change much even when you get to the tighter stuff. We turn off the expressway and onto the sinuous Pali road. This recently surfaced road is quite twisty and initially, I approach it with a fair amount of trepidation.

Soon, however, I find myself attacking corners with more confidence. I start braking later and harder, and because the GL AMG has those active anti-roll bars, I find ‘leaning on it’ is not really a problem either. Of course, there’s no getting away from all that mass. The brakes take a hammering if you drive it hard for a considerable period of time and performance does begin to tail off slightly.

Of the three modes, Comfort, Sport and Sport+, it’s obviously Comfort that is the most useable. The big 21-inch wheels don’t help, but the ride is so acceptable, you don’t really notice. There are a few thuds over the bigger stuff, but otherwise, the ride of this long-wheelbase monster is impressive.

The GL 63 AMG is unique. It has seven full-sized seats, delivers real luxury, genuine performance, loads of fun and thoroughbred driving manners, all wrapped up in one imposing package. Yes, it costs Rs 1.6 crore (ex-showroom, Mumbai) and the running costs of the petrol V8 will be huge, but if you want to have your cake and eat it too, this is the SUV for you. It’s easy, really; there literally is no competition.