Performance saloons or super-saloons so to say, are getting increasingly popular in our country. Last year, BMW got their version of it to our shores and just a few weeks back, Audi launched the S6. So how could Mercedes stay back in that race? Just a month after bringing out the refreshed E-Class, they've raised the bar with a mental version of the E, the E63 AMG.Under the bonnet of this rather subtle-looking, yet extremely powerful four-door sedan is an AMG-tuned, 5,461cc V8 bi-turbo petrol engine. And all of that means it can churn out a whopping 550bhp of power and an earth-shattering 720Nm of spin. Yes, 720Nm of it. The two blowers fitted to this engine help develop this massive torque figure right from 1,750rpm going up to 5,250 revs, leaving no hint of lag whatsoever through the rev range.All of that firepower is channelled to the rear wheels through an AMG Speedshift dual-clutch seven-speed transmission. You get four modes to choose how fast you want the transmission to react and shift through the ratios. You have the Comfort mode for relaxed city driving and then you have the Sport mode when you're in the mood for some fun. And if you want even quicker shifts, you have the Sport+ mode. For no intervention from the computers, you also have the Manual mode. And when we say 'no intervention', it's really a 'no intervention' mode. It won't shift up even when the engine hits the redline, unlike most other manual modes. Although there's little to complain about this transmission, it's still not as quick as the Audi's S-Tronic seven-speeder.To ensure the rear wheels don't just spin violently with all that power and torque they're supplied with, you have the 'Race Start' mode (Merc's version of launch control). And with that, the E63 cracks a claimed ton in just 4.2 seconds. And if you ask us about the braking, the E63 sheds its pace quicker than it puts on.The E63's steering is on the lighter side by sportscar standards, but don't get us wrong here. It's one precise piece of machinery. It'll point the nose exactly where you want it to. And when you get the tail kicking out at a bend, it'll be bang-on in getting it back in shape without much embarrassment.The suspension has two settings for the dampers. But you'll have to wait till we get our hands on the E63 on public roads to analyse the ride quality. It's almost impossible to do that on the BIC's smooth tarmac.On the outside, the E63 doesn't look as mental as it drives. It has the same single-piece quad headlamps around the big grille with the three-pointed star, just that there's just one thick slat running the length of the grille on this AMG, as against two found on its more docile twin. Below the headlamps, there's a large mesh grille with a splitter to help you distinguish the AMG easily. Apart from the reworked bumpers, quad exhausts and the badging, most bits are identical to the regular E-Class. Albeit there's a lot of carbon fibre that has gone into the making of this E63 AMG. There's a lot of it on the front lip, on the engine cover and some of it on the interior too.In spite of being a sportscar in a sedan outfit, the E63 doesn't lose out on the creature comforts. It has a LCD display for the back-seaters with a multi-CD player, a reversing camera and the Active Park Assist system. It also gets the dynamic seat package which holds you tight while you push the E63 hard into corners. The gear lever has been moved to the conventional position from behind the steering. On the safety front, it gets eight airbags to keep you unscathed in case things go out of control.The E63 AMG sees straight into the eyes of the BMW M5 and the Audi S6. With the output of 550bhp, it's almost as powerful as the M5. But despite that, this Merc is far too expensive compared to the other performance sedans. While the S6 is pegged at Rs 86 lakh and the M5 at Rs 96 lakh, Merc demands a full Rs 1.29 crore (all prices ex-showroom, Delhi) for this tyre-molesting, eccentric version of the E-Class.But even with this massive price tag, the E63 AMG promises to cause a riot on the racetrack and has all the features that you would need from your everyday four-door sedan.The numbers5461cc, V8 bi-turbo, petrol, 550bhp, 720Nm, 7A, 0-100\: 4.2sec (claimed), 250kph (claimed), Rs 1.29 crore (ex-showroom, Delhi)The verdictThe most powerful four-door sedan in the country. Mixes power, superb handling and practicality of a full-fledged sedan fabulously well. The price tag is a letdown though.