High Heat in Need for Speed: Heat are randomly selected night-time events that require the player to be at a certain Heat Level before they are allowed to participate.
They are the only events that reward both bank and reputation alongside performance parts, which are referred to as 'volatile parts'.
Two High Heat events are offered per night and are chosen randomly; one will require a racer to be at least Heat Level 3 and the other will require Heat Level 5. They will both offer a high amount of bank and rep as a reward, but the performance part offered depends on the player's current reputation level.
Participating in a High Heat event has a near guarantee of engaging with the Palm City Police Department, but offers the most bank and rep for a single event as well as a 'volatile part'.
A 'volatile part' is a high level performance part depending on the player's reputation level. Successfully returning to a Safe House with a 'volatile part' will unlock it for purchase through the garage and allow the player to equip their 'volatile part' to a car.