Few expenses were spared in conceiving the Porsche Panamera, but consumers will avoid at least one cost of ownership: the ignominious gas-guzzler tax.

Porsche has announced ratings for the 2010 sedan; it will get a combined figure of 18 mpg or 19 mpg from the EPA, depending on the model.

This means Porsche’s four-door foray will avoid a fairly substantial cost of ownership--a tax of up to $7,700 is levied on the most prolific guzzlers.

And dodging the federal penalty could give the Panamera a leg up on some competitors. The Maserati Quattroporte, a likely rival, was subjected to the tax for the 2009 model year, along with a range of top-shelf Mercedes and BMW cars.

Bentleys and Lamborghinis also make up a substantial portion of the list, which also includes SRT versions of the Chrysler 300, the Dodge Challenger and Viper and the Audi R8.

The Panamera will check in with ratings of 16 mpg in the city and 24 mpg on the highway (19 combined) for the S and 4S models, which pack 400 hp from a V8 engine.

The Turbo variant will get 15 mpg in the city and 23 on the highway for a combined rating of 18 mpg. It has a potent 500 hp under the hood.

Still, the added guzzler tax may be only an annoyance to many Porsche customers. The S is $89,800, the 4S (all-wheel drive) is $93,800 and the Turbo (also with all-wheel drive) is $132,600.