Kia continues to climb upmarket, and the introduction of the new 2006.5 Kia Optima is a primary example.

This newest Optima features new engines that are more powerful and more efficient than before, and a new five-speed automatic transmission that offers improved smoothness, efficiency and acceleration performance. Highway fuel economy has been improved by as much as 10 percent over the previous-generation Optima.

Higher quality materials and improved fit and finish create a more comfortable interior. More powerful and fully featured audio selections entertain and soothe during trying drives. A lengthened body and higher roof add roominess. A new platform with a longer wheelbase and updated suspension combine with larger wheels and tires to deliver a smoother ride and more responsive handling.

It's priced aggressively, too, with the manufacturer's suggested retail price for the base LX model a mere $160 more than its predecessor, and that's with the addition of important safety features. The uplevel EX model's MSRP jumps $1500, but again, this is with the new safety features, added creature comforts and improved sound deadening.

Two important accident-avoidance features, antilock brakes and electronic stability control, are available only as options, but are remarkably affordable.

The competition hasn't stood still, of course. And at some levels, like on the top rungs of the Honda Accord and Toyota Camry lines, even this newest Optima doesn't pretend to belong. But it's still a marked step up from its predecessor and as such, a very impressive package.

A cautionary note, however, regarding our repeated use of the word newest. For a while, there are likely to be two different Optimas in dealer showrooms labeled as 2006 models. One is the final iteration of the first-generation Optima. The other, and the one that's the subject of this review, is the first of the second-generation. Kia nominally calls this latter Optima a 2006.5 model, although it is, in fact if not officially, the 2007 Optima. This confusing overlap results from an arcane U.S. government regulation rooted in the yesteryear of automotive time when all new models appeared in showrooms in the fall of the preceding calendar year. Thus, if a U.S.-specification car today is first built in, say, the fall of 2005, as this Optima was in South Korea, it cannot legally be designated a 2007 model car. And for some silly reason, officials at the Korean companies actually think the year starts on January 1 and ends December 31.

Boiled down, the message here is, make sure you're looking at the new version as it's substantially improved over the outgoing version.