STERLING HEIGHTS, Michigan (AP) Chrysler Group wants to show the world that it’s serious about mid-size sedans.

After years of disappointing sales, the company yesterday launched production of the revamped Chrysler 200 which replaces the Sebring and the Dodge Avenger. The cars have a new look, new engines and hundreds of other changes designed to lure back customers who have fled Chrysler in recent years, scared off by its financial troubles and its reputation for poor quality.

Chrysler CEO Sergio Marchionne said the company spent $300 million revamping the cars. Both go on sale this month, starting at just under $20,000.

“The Chrysler 200 is the first step in rejuvenating the Chrysler brand,” Marchionne told 1,200 workers at the suburban Detroit plant where the sedans are made. The company is so bullish about the new products that it plans to hire 900 more workers and add a second shift to the plant later this winter.

Chrysler is aiming to be a true competitor in the unforgiving US mid-size car segment. The segment is the largest in the US, accounting for nearly one in five vehicles sold last year, and it’s the home of perennial best-sellers like the Toyota Camry and Honda Accord.

The 200 represents the biggest change, starting with its name. Its predecessor, the Sebring, was redesigned in 2006 but fell far short of the competition in style, handling and power.

sIt came out at a time when Chrysler was fighting for resources under its former owner, Daimler AG, and it was hammered for its chintzy materials and rattling performance on the road. It was quickly eclipsed by newer, better cars such as the Chevrolet Malibu, Ford Fusion and Hyundai Sonata.