The IS slips through the air with quiet stability. In addition to the distinct aerodynamic wedge of the overall shape, a number of small details contribute to the exceptional coefficient of drag (0.28). A front underbody structure creates downforce between the front wheels, a small air kicker integrated in the taillamps helps separate turbulence from the rear corners and reduces drag, and a small trunklid spoiler increases rear downforce.

Interior Features

Lush with creature comfort, trimmed with upscale materials, and crackling with electronic wizardry, the interior environment of the IS sport sedans is pure Lexus. But the cabin is more sports car than family sedan.

A prominent central console clearly establishes the driver and front-passenger zones. The controls wrap around the driver with every gauge and switch within easy scrutiny or close reach. The Optitron gauges are large and easy to read, and their light-saber indicator needles and dynamic redline indication are cool modern. The keyless entry and pushbutton ignition is handy.

Leather upholstery comes standard on the IS 250 and IS 350 with metallic accents appropriately placed around the cabin. The IS 250 AWD comes with perforated leather trim and beautifully crafted bird's-eye maple accents. Each piece is hewn from a single chunk of wood to ensure a perfect match from panel to panel.

The heated and ventilated front seats are a must-have. They come standard on IS 250 AWD and are available on the other models. Once you've tried these seats, there's no going back.

The climate control system features a sophisticated temperature calculation system called Neural-Net, a humidity sensor, a micro dust and pollen filler and, in IS 350, a smog sensor that detects excessive hydrocarbons and automatically reverts to a special recirculation mode until the atmosphere clears.

Driving Impressions

The Lexus IS in both rear- and all-wheel-drive forms is quick and easy to drive. It can pull serious Gs in the corners and it stops with authority. In short, these cars are serious sports sedans that rival the BMW 3 Series cars.

The IS 250 AWD is the best choice if winter weather invades your neck of the woods, when the all-wheel-drive system's increased grip is most welcome. The AWD model is heavier than the two-wheel-drive versions, but the IS 250 AWD hauled us over the San Gabriel Mountains on Angeles Crest Highway above Los Angeles without exposing any dire penalties due to its weight.

The IS 350 is the quickest model. Its muscular torque and free-revving engine delivers strong acceleration performance, something we saw driving one at Willow Springs raceway.

We drove several examples of the IS models at competition speeds relentlessly in temperatures that rose above 110 degrees and not one of them stumbled or misfired. Because of the hot, slippery track surface, the tires constantly fought for grip, but the advanced chassis electronics made it easier to keep the cars on the pavement. The inherent balance of the IS models made it easy to push it to the limit, causing the electronic aids to step in and dampen the thrill.

We prefer the automatic over the manual. The automatic is very responsive and offers the driver the ability to shift semi-manually using paddles on the steering wheels. The IS 250's manual six-speed isn't quite good enough to make us opt for it in lieu of the optional automatic. The automatic offers the driver more control over shifting when desired, but the computer steps in to protect against potentially damaging mis-selection of gears.

Summary

The Lexus IS 250 and IS 350 are true rear-wheel-drive sports sedans. They're quick and fun to drive. The IS 250 is a very enjoyable car. The IS 350 adds abundant power to the equation. And the IS 250 AWD boasts winter weather capability. Regardless of model, this is an easy car to drive quickly as it bonds with the driver, benefits of its balanced chassis and advanced electronic stability control systems. In fact, this bond that the car establishes with the driver is a key element for a great sports sedan.

NewCarTestDrive.com correspondent Greg N. Brown filed this report from Southern California

Model Line Overview

Model lineup:Lexus IS 250 6-speed manual ($30,255); IS 250 six-speed automatic ($31,425); IS 250 AWD ($34,285); IS 350 ($35,705)

Engines:204-hp 2.5-liter dohc 24-valve V6; 306-hp 3.5-liter dohc 24-valve V6

Transmissions:6-speed manual; 6-speed paddle-shift automatic

Safety equipment (standard):dual-stage front airbags, front seat-mounted side airbags, front and rear side curtain airbags, three-point belts for all five seats, automatic locking retractor for all positions except driver, who gets emergency locking retractor, ABS with electronic brake force distribution and brake assist, traction control, Vehicle Stability Control