The following is a list of every vehicle type in the game and the recommended vehicle for Race and GTA Race modes:

TYPE - VEHICLE
Supercars - Comet
Sports - Coquette
Muscle - Sabre GT
2 Door - Ruiner
4 Door - Sultan
Executive - Cognoscenti has higher top speed, PMP 600 has quicker acceleration.
Modern - Sentinal
Vintage - Peyote
Police - FIB Buffalo
People Carrier - Rebla has higher top speed, Habanero has quicker acceleration.
SUV - Huntley Sport
Pickup - Contender
Vans - Burrito
Service - Ambulance
Trucks - Fire Truck
Motorcycles - NRG 900
Boats - Jetmax
Helicopters - Annihilato