DETROIT – GM’s Buick division has announced drivetrain changes for its Regal, including a new automatic transmission on models available now, and eAssist, as standard, on the 2013 model-year edition of the sedan.

The Regal GS will come with a 2.0L turbocharged Ecotec engine, capable of producing 270 hp. The engine can now be equipped with a six-speed Aisin AF40 automatic transmission with Driver Shift Control is now offered as a no-cost option instead of the existing six-speed manual transmission. A driver can set the car’s Interactive Drive Control System to “GS” mode, which enables the transmission to deliver firmer shifts, aiding performance, according to GM. Acceleration matches the manual with an estimated 0-60 mph time of 6.7 seconds.

GM said eAssist will be standard on the Regal after the automaker discontinues producing the 2.4L base model. Both the Regal Turbo and GS will remain available, according to GM. The company added that the Regal with eAssist achieves an EPA-estimated 36 highway mpg.

For the 2012 model year, eAssist became standard for the larger LaCrosse luxury sedan. Offered at the same price as the V6, eAssist is already outselling its hybrid competitors and is projected to grow in popularity this year.

GM said it will announce pricing and the on-sale date for the Regal lineup later in the year.