The 2007 Kia Optima is for all intents and purposes an all-new car, thoroughly revised from the tires up (though an arcane federal regulation required that a handful were sold as 2006.5 models). It's one of the best Korean-designed automobiles yet. Like most cars in the ultra-competitive field of mid-size sedans, the Optima offers a choice of four-cylinder or V6 power in a front-wheel drive chassis.

The base 2.4-liter four-cylinder is strong, particularly with the manual transmission. Both the four-cylinder and upgrade 2.7-liter V6 are more efficient than the engines in pre-2007 models, and a new five-speed automatic improves fuel economy, acceleration and overall smoothness. EPA mileage ratings have improved roughly 10 percent compared to the 2006 Optima.

Inside, solid design, more attractive materials and improved fit and finish make the Optima a pleasant place to spend time. The standard six-speaker audio system is not bad at all; the upgrade in the Optima EX is tuned by Infinity, with a standard six-CD changer. A longer body and taller roof create more room inside. As importantly, a new, more rigid chassis delivers an overall tightness and smoothness Korean brands lacked just a few years ago.

Add a slightly longer wheelbase, improved suspension and larger standard wheels and tires, and the 2007 Optima is also quite pleasant to drive in nearly all circumstances.

Optima is priced aggressively, beating just about everything in the class without stripping conveniences. Standard passive safety features, including curtain-style head protection airbags for all outboard seats, match the class benchmark.

Kia's quality has steadily and significantly improved, according to customer satisfaction surveys, and the Optima's warranty is one of the best available.

All things considered, the Optima still falls short of the best-selling mid-sized sedans in certain, mostly subtle ways. But those shortcomings are fewer than ever before, and many are so subtle that budget-minded buyers may not notice or care. Bottom line, the Optima is a good car at a compelling price.