Anarchy: Rush Hour Trophies
Buy all cars
Buy all possible cars.

Self-explanatory. All the cars in the game must be purchased from the "Car Dealer", except one, the "Rampage". That car is given to you. The game starts you off with $50,000. There are 39 remaining cars, out of 40 total. To get them all, you will need to accumulate $15,454,000 million, in addition to what you already spent on Adrenalin Devices and Accessories.

Suggested way to grind away all that cash is after the Story completion, keep doing Sprint and Checkpoint races with the highest payout. When the available payout is lower than $50,000 (minus the buy-in), then enter the "Stunts at the Louvre" event until a better paying one appears.