The number of Buick Regal variants is set to double this fall, as the base Regal and Regal Turbo are joined by a 270-hp Regal GS and an economy-minded Regal with a mild-hybrid system called eAssist. With the showroom debut of the latter two cars drawing nearer, the company announced pricing for both today: The 2012 Regal GS will start at $35,310, while the Regal with eAssist will begin at $29,530.

The Regal GS—GS stands for Gran Sport, an appellation for the hottest Buicks going back to the 1960s—will come with a 270-hp, turbocharged 2.0-liter four-cylinder engine that makes 295 lb-ft of torque. A six-speed manual transmission is standard, and a six-speed auto will land on the options sheet later in 2012. While the entry price is steep, the Regal GS will come very well equipped. In addition to the aggressive body kit and unique front fascia, the GS features standard 19-inch rims, front and rear parking assist, a leather-slathered interior, special flat-bottom steering wheel, metal pedals, and a Harman Kardon sound system. Still, for this sportiest of Regals, Buick is asking a lot of coin over the 220-hp Regal Turbo, which starts at $29,720. The automaker says the GS should be good for 27 highway miles per gallon of gas.

Buick-loyal shoppers who are more concerned about fuel economy will probably be interested in the $29,530 Regal with eAssist. (As a quick refresher from our earlier coverage, the eAssist system is a very mild hybrid setup with a small motor-generator and battery pack.) This is $2000 more expensive than an otherwise-identical non-eAssisted Regal with the same 182-hp, 2.4-liter four-cylinder engine. With gas near $4, Buick says the added cost of the eAssist system will take three and a half years to recoup in fuel savings.

While the Regal eAssist’s 25-mpg-city/36-highway fuel economy rating is decent for a vehicle that weighs in at about 3600 pounds, it will face stiff competition from other efficient vehicles around the $30,000 mark. The first rival sits just across the showroom; it’s the Buick LaCrosse, which comes standard with the same eAssist system, boasts identical fuel economy numbers to those of the Regal eAssist, and is only marginally more expensive, starting at $30,820. The full-on hybrid version of the Lincoln MKZ is priced much higher, at $35,520, but does offer an EPA fuel economy rating of 41 mpg city/36 highway. In the non-hybrid, efficiency-minded, still-somewhat-premium-brand arena, a Volkswagen Passat TDI with an automatic transmission starts at $28,665 and has an EPA rating of 30/40.

We haven’t been blown away by the Regals we’ve sampled thus far—check out our review of the Regal Turbo with a manual transmission for an example—but we look forward to trying both new flavors of Regal to see if they justify their rather high asking prices. Check back soon for reviews of both.

By Justin Berkowitz