This is the first turbocharged car Acura has ever made. Honda has been the technology leader with small engines for a long time and this 2.3-liter turbo is about as high-tech as they come. The turbocharger changes the power characteristics quite a lot from the more peaky Acura TSX, although it doesn't smooth out the engine. There's 260 pound-feet of torque, and no turbo lag, but when the transmission is in Drive, it kicks up and down when you're driving casually uphill. Apparently the turbo confuses it, something we'd seen in the past with Volkswagen's 2.0T turbos. To stop it, you have to use the Sport, or manual, mode.

In the manual mode, the transmission obeys your commands except when you downshift at an engine speed it thinks is too high, or upshift at one it thinks is too low. Then at least it tells you that it's rejected your input by flashing; some systems indicate the car is in the gear you've chosen, even if they don't shift to it.

In stop-and-go freeway traffic, we found it difficult to accelerate smoothly. Acura invented drive-by-wire throttle, and, because so many other cars with this electronic system also have hair-trigger throttles, we wonder if the system still has a ways to go. In any case, this does not make the RDX a great commuter car in heavy traffic.

A bigger flaw than a quick throttle or unsettled transmission is the ride. A front-seat passenger said she could feel every bump, especially on the freeway. We could feel them too. It was like a jolt, over the freeway ridges.

Of course, this firmness in the suspension enables the RDX to perform like a sports car around the corners. Acura boasts that it will out-corner a BMW X3, which was developed on the Nurburgring circuit in Germany. So, good for the RDX. But is it worth the trade-off, if the suspension can't also offer a comfortable ride on the freeway? Maybe. You decide.

We drove one RDX in California then spent a week in another RDX in the Northwest, just in time for snow and ice. We tested the ABS by slamming on the brakes going down a steep hill with hard-packed snow at 20 miles per hour. The response was beautiful; it took a long time to get stopped, maybe 100 feet, but we were able to steer anywhere we wanted to, without sliding, while our foot was mashed to the pedal (as we watched 10 inches of snow slide off the roof and down onto the hood). We should point out that the P235/55R18 Michelin Pilot tires are considered high-performance all-season, meaning they weren't made for this sort of thing; all-season generally means three seasons.

Then we went to a slushy parking lot, and tried to cut donuts at hard throttle, to test the stability control, called VSA. The RDX just turned its tight circles, 39.1 feet, without sliding. Pretty amazing.

A couple days later the slush froze into sheer, lumpy ice. We returned to the bottom of our steep hill. The city had put up barriers because the road was considered dangerous. We drove around the barrier and charged uphill, considering it our duty to New Car Test Drive readers. It was fascinating to feel the all-wheel drive work, and watch the readout on the instrument panel indicate with bars which of the four tires was getting the torque, based on how slippery it was under each tire at any moment. The RDX struggled, and once came to a complete halt, not spinning, just shutting down the throttle because it couldn't find grip. The RDX slid downhill backwards on the ice, with the brake pedal mashed; the ABS did not appear to be working, maybe because it had started sliding from a dead stop, so the sensors didn't know it was sliding. The RDX found a dry patch under one wheel, and when that wheel bit and held onto the patch, the vehicle turned perpendicular in the road.

Both front wheels were on a dry spot now. We gave it a lot of gas, turned tightly back uphill, and looked for spots that weren't so icy. The all-wheel-drive system, which can send 70 percent of its torque to the rear wheels, struggled for grip, its computer sensors playing the throttle and brakes on and off at four separate wheels at lightning speed, and we made it to the top. Great stuff, especially with those high-performance wide profile tires.

In winter conditions like these, you can't beat a high-tech vehicle, with all-wheel drive, anti-lock brakes, electronic stability control, six air bags and xenon headlamps. Not to mention heated seats and heated mirrors.