AMG built race engines in the 1970s, then expanded into speed modifications for Mercedes-Benz sedans, and eventually began installing complete go-fast packages on customers' cars. The Germans don't use the word "sleeper" to describe a car, but the folks at AMG understand the concept. Their early uber-cruisers were so understated yet so potent, Daimler formed a partnership with AMG in 1999 and bought the company outright in 2005.

Of course part of their cars' appeal is horsepower. AMG's current engine displaces 6.2L (379 CID) and generates 518 hp and 460 foot-pounds of torque. Serious power, but similar power is also available from BMW, Jaguar, Porsche and Audi. That's why Mornhinweg has decided to "use other means" of enhancing performance.

I have often wondered when enough would be enough. Engines have improved with each new generation, not just in overall power but also in refinement and reliability. In the Muscle Car days, 500 hp engines were lumpy-cam, ill-tempered, worked-to-the-limit beasts that, as the saying went, could pass anything except a gas station. The new AMG engine returns almost twice the fuel mileage, is reliable as any other production engine and has electronic controls so refined your grandmother could drive it without having a clue the car is capable of almost 200 mph.

Fifty years ago, Colin Chapman focused on power-to-weight ratio. Less weight means the job gets done with less power, so Chapman omitted anything that wasn't absolutely necessary. The most famous result was the Lotus Seven, basically a road-legal racecar that extracted serious fun from a mere 107 hp.

Chapman is long gone, but his design philosophy still guides the company. The 2009 Lotus Europa weighs less than 2,200 pounds and achieves stellar performance using "only" 200 hp. But it is a minimalist car, and that approach is not entirely suitable for AMG's gentlemen's cruisers.

Mornhinweg's performance will come from a combination of reduced weight and increased specific power (horsepower-to-displacement ratio). Muscle Car engines achieved 1 hp per cubic inch, and 40 years later, the AMG engine produces 1.3 using basically the same techniques: high compression, tuned intake and exhaust and high rpm. But newer engines are easily reaching a specific power ratio of 1.7 using direct fuel injection and turbochargers tuned for low- and mid-range power. Today's Audi A4 engine produces 207 hp from only 122 cubic inches (2.0L), and the 2010 Ford Taurus SHO engine will make 365 hp from 213 inches (3.5L). In these engines, the torque curve peaks early and remains almost flat, making them feel bigger but consume no more fuel than others of the same displacement (if you can keep your foot out of it).

Every manufacturer is moving toward higher specific power to decrease their fuel burn. This could spawn a new era of high-performance cars, but with the increasing focus on green technologies such as hybrid and all-electric powertrains, it also could be the last hurrah for our beloved piston engines. Until then, I intend to enjoy the ride with the music turned up loud.