High Stakes is a special race type featured in the fourth Need for Speed instalment only.
Very similar to duels in other NFS games, where two racers are competing each other with no presence of police. The main difference is, that the winner gets the car of her/his defeated rival, hence the name. Other than that, High Stakes events take place right after the player has won a tour.
Unfortunately High Stakes events cannot be replayed, meaning the player will permanently lose their car after not winning such an event. In the PSX version this mode is available from the start it involves 2 players and the winning player gets the losing player's car transferred to their memory card while in the PC version its unlocked after completing all the events here you race against the AI.