There are 5 "Hidden Cars" in Mafia: Definitive Edition. You can find the cars in "Free Ride" mode. But first you'll have to collect the Post Cards from Lucas Bertone's Autoservice. They are mandatory to make the cars spawn. Subsequent postcards will be available as you progress through the main story of the game.
Achievements / Trophies: On the Trail (Find a hidden car), Car Thief Number One (Find all of the hidden cars)
DisorderFirst, you need to collect the postcard, which you will find in Lucas Bertone's Autoservice.
Go to the Vevoda motel located near the dam.
Open the door to the garage behind the motel and you will find a car inside.
Flame SpearFirst, you need to collect the postcard, which you will find in Lucas Bertone's Autoservice.
The car is parked in a garage on the Central Island.
Just open the door to the garage and the car will be yours.
Lassier V16 AppolyonFirst, you need to collect the postcard, which you will find in Lucas Bertone's Autoservice.
Then you must go to Beech Hill and open a garage at one of the mansions.
Be prepared that when you do this you will be attacked by a man inside.
Manta PrototypeFirst, you need to collect the postcard, which you will find in Lucas Bertone's Autoservice.
Approach the station area from the east side, climb on the crates and jump over the wall.
Go through the labyrinth of crates.
After a while you should get to the garage door.
Open this door and you will find a car inside.
Trautenberg SportFirst, you need to collect the postcard, which you will find in Lucas Bertone's Autoservice.
The car is in the warehouse. Kick out the door on the right and go inside.
Use your weapon to destroy the boxes that block your way.
Continue and destroy more crates until you reach the car.
To open the door switch three levers on the wall.
