The STi is another beast entirely, and the difference is even more pronounced in 2006. With 300 horsepower, the STi boasts a power-to-weight ratio that will embarrass a lot of expensive sport sedans and more than a few sports cars. Everything from its transmission to suspension to brakes is tuned to take advantage of all that horsepower.

Give it a little gas and this car jumps. Dip the pedal further, say another 25 percent, and the STi surges, almost angry that you haven't unhooked the leash. Floor it, and neither you nor your passenger will have any doubt what the fuss is about. The STi prefers the pedal flat. Power comes in big chunks, as opposed to the smoother fashion in the standard WRX, and the kick in the seat gets stronger the higher the engine revs. The engine is louder than the WRX's, and there's a steady, whiny humm from the heavy-duty gears in the transmission.

There's not much difference between the STi and some race cars, except that the STi has no roll cage and all its lights work. It's should therefore be no surprise that the STi is at its best on a track. On the road, its extra firm ride has its drawbacks. Even on relatively smooth pavement, the STi can feel like it's bouncing an inch or two every ten feet. We love it, at least part time, but we're not sure our tastes are shared by every buyer. We wouldn't recommend this Impreza to anyone but a committed driving enthusiast who bides his or her time during the week in anticipation of the next track day. The standard WRX has nearly all the capability most of us will ever use on the street, with less noise, less vibration and more comfort.

At the other end of the Impreza performance spectrum sits the Outback Sport (funny it's called Sport, because in our view it's always been the least sporty). Traditionally, the Outback Sport has had a bit more float than the other Imprezas, thanks to its raised suspension. It sways a bit more side-to-side during quick direction changes. The finish is not to our taste, but it gives the Outback even better capability on worn logging roads or even trails through a national forest. It's more maneuverable and responsive than most SUVs. It's more economical to operate and it's sure easy to park. It's easy to see how the Impreza Outback might appeal to a lot of buyers. If you live in the outback, the Impreza Ouback Sport makes a lot of sense.

Summary

The Subaru Impreza models are more refined and sophisticated than ever. While the Impreza 2.5i costs more than a lot of cars in its class, it comes standard with all-wheel drive, more power, and a fairly comprehensive standard equipment list. It's a great winter car in the Snow Belt, and unlike most competitors, it's available as a wagon. With its taller ride height and suspension design, the Outback Sport works well for gravel roads. The many WRX variations are true driving-enthusiast cars and fantastic daily drivers. The track-tuned WRX STi performs as well as some serious sport sedans that cost nearly twice as much. By virtually every measure, the Imprezas stack up well against the competition.

NewCarTestDrive.com correspondent J.P. Vettraino filed this report from Detroit.

Model Line Overview

Model lineup:Impreza 2.5i sedan ($18,295); 2.5i wagon ($18,295); Outback Sport wagon ($19,195); Outback Sport Limited wagon ($19,695); WRX TR sedan ($23,995); WRX sedan ($24,995) WRX wagon ($23,495); WRX Limited sedan ($27,495); WRX Limited wagon ($26,995); WRX STi ($32,995)

Engines:173-hp sohc 16-valve 2.5-liter H4; 230-hp dohc 16-valve turbocharged H4, 300-hp dohc 16-valve turbocharged H4

Transmissions:5-speed manual; 6-speed manual; 4-speed automatic

Safety equipment (standard):dual-stage front airbags, front seat side-impact airbags, ABS with electronic brake-force distribution

Basic warranty:3 years/36,000 miles

Assembled in:N/A