I caught this movie on TV tonight, and noticed that the existing page ( http://www.imcdb.org/movie_94963-The-Dead-Pool.html ) is incomplete.

Vehicles of 2 or more stars that are missing:
Oldsmobile Delta 88 - 2 stars - Harry Callahan's car in the opening sequence (identified here as being distinct from the 98 used later, yet it is inexplicably not listed: http://www.imcdb.org/vehicle_2451-Oldsmobile-98-Regency-1985.html )
Cadillac unknown - 2 stars - used by the hitmen in the opening sequence along with the Firebird
Fleetwood Southwind (Class A Motorhome) - 2 or 3 stars - scene of the first murder, model name clearly visible

Additional background cars I noticed:
Porsche 914 - 1 star - White, speeds by in the left lane during the opening sequence
Volkswagen "Beetle" [Type 1] - 1 star - opening sequence, is struck by Harry's Oldsmobile so it has sort of a role
1985-1986 Mercury Cougar - 1 star
1984+ Dodge Colt hatchback - 1 star
1967 Ford Mustang - 1 star - light blue
Plus several background cars during the (awesome) chase sequence (I think I saw a green MG and a Renault LeCar)