DETROIT – Redesigning an iconic car is a challenge, one faced by Chrysler LLC designers as they work on the next-generation 300 sedan.

Putting a fresh spin on the successful rear-wheel-drive model, which debuted to great buzz and strong sales in spring 2004, is the hard part, vehicle designer Lou Gasevski tells Ward’s.

The shape is so unique, “you keep repeating the same thing,” he says following a presentation to the Automotive Press Association here. “It’s easy to design something that’s new, like a concept car. But to design a new model and make it successful, that takes a master.”

Joe Dehner is in charge of the 300 redesign, but all of Chrysler’s relatively small design staff of 23 is working on the vehicle, which Gasevski says is “in process – almost done.”

He invokes Porsche AG when describing how Chrysler is approaching the 300 redesign. “They change a little bit about the car, but it’s still modern,” Gasevski says of the brand’s iconic sports cars.

Not wanting to mess too much with success means the new 300 will have an “evolutionary” exterior, he says. However, the interior will make a “huge leap.”

Chrysler has been widely criticized for what many industry analysts consider subpar interiors. Gasevski admits it was difficult to work with the cheap, hard plastics the auto maker once relied on.

But things are different under new owner Cerberus Capital LP, he says, noting 80% of the design changes to existing models instituted under CEO Bob Nardelli are complete.

“The products coming out in 2011, 2012 will be very competitive with Asian (models) as far as content, materials, fit-and-finish,” Gasevski says of future Chrysler, Dodge and Jeep vehicles. Cerberus Chairman Steven Feinberg is “tough and he wants to deliver a quality product with advanced technology.”

One advanced technology for the next-generation 300 may be a dual viewing screen. The design allows the primary screen to project a movie to the front-seat passenger, while the driver can view maps or vehicle information. Drivers are prohibited by law from watching movies.

On another front, Gasevski says Chrysler “is working on multiple small-car projects,” including one in Japan. He declines to confirm if the Japan-based project is the new subcompact Chrysler will be building on Nissan Motor Co. Ltd.’s B-platform.

The two auto makers announced such a model will be built at Nissan’s Oppama, Japan, plant and debut in North America in 2010.

Chrysler also has a deal with China’s Chery Automobile Co. Ltd. to build 12 vehicles in three segments for various markets.

cschweinsberg@wardsauto.com