ok

well, the Deville, the 911 and the Mustang would have 3 stars then

used by principal characters, but are they used a lot in the movie? If they are visible only in few scenes they usually get 3 stars

The supermarket parking ones appear just only a second, so they're not very important.
And yes, the Mustang, the Sebring, the 911 and the Deville are used by principal characters.

Thanks
http://www.imcdb.org/movie_335559-Win-a-Date-with-Tad-Hamilton!.html
I am a little surprised by the star-rating... so many 4-star cars? And the "2 unknown cars" pic is only 1-star?
For the 1-star cars on the supermarket parking, are they seen for long time or somewhat important? Because they are not very special models to be included as background cars...

Ferrari F355 Spider (1 star)

Chevrolet Corvette C5 Targa (1 star)

Lincoln Town Car Stretch Limo (4 stars)

Porsche 911 (996) Carrera Cabriolet (4 stars)

Ford Aerostar (1 star)

Ford F-150 single cab (1 star)

Porsche Cayenne Turbo (1 star)

Ford Crown Victoria (2 stars)

Cadillac Deville Limo (4 stars)

Ford Taurus (2 stars)

Ford LTD Wagon (i think) (1 star)

Hummer H2 (2 stars)

Chevrolet Lumina (1 star)

Ford Mustang MkI (4 stars)

Chrysler Sebring Convertible (4 stars)

2 unknown cars (1 star)

unknown (1 star)