Anyone who has driven a Lexus GX 470 to extremes has probably come away from the experience impressed with the SUV’s off-roading capability but disappointed in its on-road handling. The GX 470, as luxurious as it may be, is based on a true off-roader that in other parts of the world is labeled a Toyota. And true off-roaders are not usually any good to drive as daily commuters from the suburbs to the city. Although, given the state of this nation’s roadways, we’ll concede that daily commutes can sometimes be considered off-roading. But that’s another story.

Equipped with an option called Kinetic Dynamic Suspension System (KDSS), the Lexus GX 470 is a far more civilized sport-ute than it is without KDSS. Since early 2004, KDSS has been available to combat the excessive body motion that plagues the GX 470, making it feel unstable and sluggish on paved roads and causing discomfort on backwoods trails.

To reacquaint ourselves with the GX 470’s penchant for producing motion sickness, we drove one on a tough handling course littered with dirt moguls, trenches, and rocks. Without KDSS, the stock GX 470 produced significant head toss, lurched on its suspension, and divorced its tires from the difficult trail. On another section intended to simulate highway driving, the GX keeled over in turns and tossed its considerable weight around, making it unstable in certain conditions.

KDSS resolves most of these negative handling traits. Simple cylinders filled with hydraulic fluid and located inside larger front and rear stabilizer bars allow KDSS to increase or reduce the bars’ roll stiffness as conditions require. On the highway, this translates to stiffer stabilizer bars that produce less body roll and equalize wheel loading for a more controlled feel from behind the wheel and better response at the tires’ contact patches. Off-road, KDSS reduces stabilizer bar stiffness to increase wheel travel, resulting in less body motion and head toss on tough terrain while keeping the rubber planted on terra firma.

Included in the $1,800 Sport Package or available as a stand-alone option for $1,750, KDSS has been added to just 12 percent of the GX 470’s that have rolled off showroom floors in 2005. That’s an appalling figure, given how KDSS totally transforms the driving experience. C’mon, GX 470 buyers, what’s another coupla grand when you’re already spending 50 g’s? KDSS is definitely worth it for the more sure-footed highway response alone. And a more responsive vehicle is an inherently safer vehicle.