You could argue that there are two types of buyers looking for fuel efficiency.

The first are those who want absolutely the most gas-sipping car they can get their hands on--the Prius, the Volts and the VW TDIs of this world.

The second want cars like the Porsche Panamera Diesel luxury sport sedan--a car that offers the speed and amenities you expect from a prestige product, without having to pay a fortune on fuel bills.

British car journalist Chris Harris has been running just such a car for a few months now, and praises its varied qualities. But to answer claims that the Panamera Diesel simply isn't fast enough for a Porsche, Chris took it to the track to lay down some numbers.

Subjectively, he has no problem with the performance, even considering the other high-end vehicles he drives with regularity.

After all, the V-6 diesel's 247-horsepower, and 406 pounds-feet of torque developed from only 1,750rpm, can make for pretty rapid progress on the road. He also likes the build quality, handling, and even the divisive styling.

On the track, the car turns in a 6.9 second 0-60mph run--a tenth of a second off Porsche's claims--and on Millbrook's high-speed bowl (where we recently drove BMW's ActiveHybrid 5 at 100mph-plus speeds) the Porsche registers 150 mph.

However irrelevant some of these numbers are in daily driving, the idea is that--even judged against Porsche's high standards--the Panamera Diesel is still a quick car in real-world use.

Not only that, but it's a car that Chris has been achieving a regular 33-37 mpg from during daily use--where a more expensive Panamera Hybrid gets 25 mpg combined from the EPA, and a regular, 3.6-liter V-6 gasoline Panamera only 21 combined.

That leaves us with just one question--with a diesel Porsche Cayenne SUV confirmed for the U.S, when are we getting the diesel Panamera?...


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