We must remember that AMG's specialty is not the exterior or the interior of the car: the difference lies in the engine and in the handling.  In that respect, AMG successfully placed a 5.5-liter SOHC 24-valve V8 engine into the E-class' bonnet.  This V8 engine can generate 354 bhp at a respectable 5500-rpm and a walloping 530 Nm of torque at a low 3000 rpm.  This in turn generates into a 4-door sedan that can accelerate to 60 mph in 5.4 seconds and reach an electronically limited top speed of 155 mph.  The E55 can also corner and steer as well into the corners as a proper sports car.  With ESP (electronic stability program) the E55 feels very, very safe and won't slide out during manic cornering speeds.  Huge 4-wheel ventilated disc brakes with ABS can as mentioned earlier, outbrake a Ferrari F40 and a Honda NSX. 

The Mercedes-Benz E55 AMG truly became a sports car alternative.  A sports car with 4-doors and can seat 5 and hold lots of luggage.  In fact, Mercedes is offering this mad German car in two variants: as a sedan and as a wagon.  Just imagine this: a 230 kph wagon?!  Truly, AMG and Mercedes and their wonderful sounding manic V8 beat the BMW M5 to the ground. 

The E55 AMG held the throne for so long, that is, until BMW came up with its new BMW M5.  Now, the playing field is much better for these two German rivals.  BMW M (which stands for Motorsport) has been developing the most powerful engine they have released ever (with the exception of the McLaren F1's 6.1 liter V12).  After years of working and hard labor, M has come up with a new engine that would secure the mad sedan throne once more: a 5.0-liter DOHC 32 valve V8. 

Though smaller in displacement that the Merc's the BMW M5's engine uses VANOS technology (also seen in the McLaren F1 and new BMW 3-series engines) which changes the flow of air and fuel in the engine to maximize fuel burning and efficiently which results into better horsepower and torque rating than normal.  This is much like Honda's VTEC technology. 

AMG replaces the standard E-class' recirculating ball steering and placed rack-and-pinion instead.  The result? A better handling car, but not as quick as the M5.
 
Low profile tires and stiffened suspension may cause difference when compared to E-class' ride. Nonetheless, its still better than the BMW M5 or Jaguar's XJR for that matter.
 
Cabin is standard Merc fare: solid granite feel and high-quality materials.  Nonetheless, its  somber, though commanding.