I looked through IGN's database of GTA IV's vehicles... Suprisingly, some of those we guessed were wrong guesses. I don't know how true this database is though. I'll rate them in alphabetical order & list their SPEED, HANDLING & DURABILITY respectively with A being the best & D being the poorest. Here goes...
Ambulance >> Chevrolet Ambulance >> D,D,A
Banshee >> Dodge Viper >> A,B,C
Benson >> Ford F-650 >> D,D,A
Biff >> Mack Pinnacle >> D,D,A
Blista Compact >> Honda CRX >> C,C,C
Bobcat >> GMC C/K Westside >> D,D,B
Bucanneer >> Oldsmobile Cutlass >> C,C,C
Bus >> East Lancs Greenway >> D,D,A
Cabby(Limited) >> Chrylser Town & Country >> D,D,C
Cavalcade >> Cadillac Escalade >> C,D,B
Cavalcade FXT >> Cadillac Escalade EXT >> C,D,B
Chavos >> Subaru Legacy >> C,C,C
Cognoscenti >> Maybach 62 >> C,B,C
Comet >> Porsche 911 >> A,A,C
Contender >> Ford F-150 >> D,C,C
Coquette >> Chevrolet Corvette >> A,B,C
DF8-90 >> BMW 6-Series >> B,C,C
Dilettante >> Toyota Prius >> D,D,C
Dukes >> Dodge Charger >> C,C,C
Emperor >> Cadillac Brougham >> D,D,C
Enforcer >> International Navistar >> D,D,A
Esperanto >> Chevrolet Malibu >> D,C,C
Faction >> Buick Grand National >> B,C,C
***gio >> Piaggio BV250 >> D,C,D
Feltzer >> Mercedes-Benz SLK >> B,B,C
Feroci >> Infinti I30 >> C,C,C
FIB Buffalo >> Dodge Charger >> B,B,C
Fortune >> Ford Thunderbird >> C,C,C
Freeway >> Harley-Davidson Sportster >> A,C,D
Futo >> Toyota AE86 Coupe >> B,B,C
Hanabero >> Lexus RX >> C,D,C
Huntley Sport >> Range Rover Sport >> C,C,B
Infernus >> Lamborghini Murcielago >> A,A,D
Ingot >> Subaru Loyal >> D,C,C
Intruder >> Infiniti M >> C,C,C
Landstalker >> Ford Expidition >> C,C,B
Manana >> Cadillac Eldorado >> C,C,C
Marbelle >> Lincoln Continental >> D,D,C
Merit >> Chevrolet Impala >> C,C,C
Minivan >> Ford Windstar >> D,D,C
Moonbeam >> Chevrolet Astro Van >> D,C,C
Mr. Tasty >> Chevy Step Van >> D,D,B
NGR 900 >> Kawasaki Ninja 500/ Suzuki GSX-R >> A,C,D
Oracle >> BMW 7-Series >> B,C,C
Packer >> Freightliner >> D,D,A
Patriot >> Hummer H2 >> C,C,A
PCJ 600 >> Ducati Monster >> A,C,D
Phantom >> Peterbilt 389 >> D,D,A
Perennial >> Honda Odyssey (JDM) >> D,D,B
Pinnacle >> Infiniti G35 >> C,C,C
Peyote >> Lincoln Premiere >> C,C,C
PMP 600 >> Chrylser 300 >> C,C,C
Police Patrol >> Chevrolet Impala >> C,C,C
Presidente >> Cadillac CTS >> C,C,C
Primo >> Chevrolet Caprice >> D,C,C
Rancher >> Ford Broco >> D,C,C
Rebla >> Volkswagen Golf Plus >> C,C,C
Ruiner >> Pontiac Firebird/Chevrolet Camaro >> B,B,C
Sabre >> Buick Regal >> D,D,C
Sabre GT >> Ford Gran Torino Sport >> B,C,C
Schafter >> Mercedes-Benz E Class >> C,C,C
Securicar >> International Navistar >> D,D,A
Sentinel >> BMW 3-Series >> B,B,C
Speedo >> Ford E-Series >> D,D,B
Stallion >> Pontiac GTO >> C,C,C
Stratum >> Citroen BX Estate >> D,C,C
Sultan >> Lexus IS200 >> B,B,C
Super GT >> Aston Martin Vantage >> A,A,C
Taxi >> Ford Crown Victoria/Chevrolet Impala >> C,C,C
Turismo >> Ferrari F430 >> A,A,D
Uranus >> Merkur XR4Ti >> D,C,C
Vigero >> Chevrolet Camaro >> C,C,C
Vincent >> Mitsubishi Galant >> C,C,C
Virgo >> Buick Riviera >> D,D,C
Voodoo >> Chevrolet Impala >> D,D,C
Washington >> Cadillac DeVille >> C,C,C
Zombie >> Truimph Chopper >> B,C,D
[Edited by RebelCommander, 5/29/2008 2:36:42 AM]