some of you guys just pick vehicles you think look nice.
try picking the ones with the best speed and handling and price because you can always upgrade the acceleration and brakes. get one of each class of vehicle, one sedan, one super, one sports, one off-road, etc. I find it very effective to win races if you do this.
My list of best vehicles is the: Adder (Super), Carbonizzare (Sports), Dewbauchee JB 700 (Sports Classic), Dewbauchee Exemplar (Coupes), Bravado Gauntlet (Muscle), Obey Tailgater (Sedan) Weeny Issi or Dinka Blista (Compacts), Dundreary Granger (SUV), BF Injection and Sanchez (Off-Road), Dinka Double-T or Nagasaki Carbon RS (Motorcycles).
Of course some are optional as barely anyone races with coupes, sports classics or SUV. I'd like to leave room for my own personal vehicle to, so personally, I'd remove the SUV, Coupe, and Sports Classic. I don't include other vehicles from different classes such as military, emergency, vans etc. is because they're not used in races or just not so different to each other that it doesn't matter.