September loosely marks the new car season even though some 2009 models have been out since late winter. Here are 10 new or substantially renewed cars with impressive technology, performance, or environmental features. All were seen and driven at two mid-September test days for auto writers at and near Pocono Raceway in Pennsylvania at an annual event sponsored by the International Motor Press Association (IMPA).

10 Hot New Cars Slideshow: Click Here

Most eye-catching among mainstream vehicles was the 2009 Acura TL sedan (above), which cured its biggest problem - 280 hp driving only the front wheels with so much force you needed to hold the steering wheel hard when accelerating - by adding an all-wheel-drive version that employs Acura's Super-Handling All-Wheel-Drive.

SH-AWD is Acura's term for torque vectoring, or providing extra power to the outside wheels as the car goes around the corner. SH-AWD literally power-steers the car through a curve. It's great on the racetrack and a huge benefit on rainy or snow-swept roads. The all-wheel-drive version of the TL now produces 307 hp, there's an improved navigation system (Pioneer replaces longtime partner Alpine in the center stack), and there's even more room in back. Look for the TL to show up on even more 10 Best Cars lists and perhaps somebody's 10 Ugliest Cars list. The huge front medallion grille isn't to everyone's taste, although there's no mistaking the Acura brand now.

See the slide show for my 10 favorite cars from the IMPA Test Days. That's favorite as in memorable to drive, for better, or occasionally for worse, on one day when you set aside concerns about cost and fuel economy. Also see Good Clean Tech for test drives of four fascinating diesel cars with low pollution, high fuel economy, and, alas, current unavailability in the U.S.