Regulations

Every festival event has an entry specification. A car that does not meet it cannot be registered, and the player is told exactly which regulation it fails at the registration screen — never mid-event. The discipline's mechanic catches breaches before registration, to the degree their Expertise allows (Mechanics).

The rulebook is short, intentionally. The festival is not a professional series and does not pretend to be. There is no homologation process, technical passport, sealed components, balance-of-performance adjustment or post-event teardown. There is a scrutineer with a checklist, a tape measure and a set of scales, checking what matters: that the car is safe, that it is in the right class, and that it carries nothing the discipline prohibits. Cars are checked before the event and spot-checked after.

A car cannot be part-legal. Every item is checked, and one breach rejects the whole entry.

All disciplines

Safety:

• Roll cage, fixed racing seat and harness
• Working lights, functional windscreen, no exposed sharp bodywork
• Battery cut-off within the driver's reach
• Brakes and tyres in serviceable condition

Competition:

• Minimum weight by class
• Nitrous prohibited in every discipline except Drag
• Class assignment by the same performance index the city uses (Vehicle classes)

Visual and interior regulations

The rulebook governs how the car is built, not only how it performs, and this is where a city build is most often rejected:

Item	Ruling
Boot audio — subwoofers, amplifiers, screens, display panels	Prohibited outright. Unsecured mass in the back of a car on a circuit. The boot must be empty or carry only permitted equipment.
Neon — underglow, wheel-well, interior	Prohibited. No exterior lighting beyond the standard units.
Body kits	Permitted only within the discipline's dimensional limits. A wide-body kit legal in Drift is illegal in Grip. Overhang, splitter projection and wing dimensions are measured.
Interior trim	Non-structural trim, upholstery and dashboard dressing must come out. Cage, seat, harness, wheel, pedals and instruments stay.
Glass and tint	Tint above a defined limit is prohibited. Side glass may be replaced with permitted lightweight panels.
Ride height and camber	Minimum ride height enforced per discipline. Camber capped.
Livery	Unrestricted — the only part of the car's visual identity the festival does not touch. Paint, vinyls, decals and sponsor branding are entirely the team's.

This is not the game punishing customisation. It draws a line the protagonist has never had to acknowledge: the thing he made to be looked at and the thing he brings to be measured are not the same object.

Per-discipline regulations

Discipline	Drivetrain	Aspiration	Aero	Tyres	Additional
Grip	Any	Any	Wing and splitter within dimensional limits	Treaded competition tyre mandatory; slicks and drag radials prohibited	Minimum ride height, and a maximum ride height set below Sprint's minimum. Angle kit prohibited.
Drag	Any	Any; nitrous permitted	Wheelie bar mandatory; front aero unrestricted	Drag radial or slick mandatory	Parachute required above a defined trap speed
Drift	Rear-wheel drive only — front- and all-wheel drive barred	Any	No limits	Any	Angle kit mandatory; ABS must be disabled; wheelie bar prohibited
Speed	Any	Any	Stability aero mandatory, in a specification larger than the Grip and Sprint dimensional limits allow	Speed-rated tyre mandatory; treaded competition tyres are not speed-rated	Minimum brake specification; ABS must be enabled
Sprint	Any	Any	Same dimensional limits as Grip	Treaded competition tyre mandatory	Minimum ride height above Grip's maximum, for closed public roads. Angle kit prohibited.

These rules make the five disciplines mutually exclusive: no car can be legal in two of them at once (The five-car requirement).

Performance classes

Each discipline runs three competition classes, drawn from the city's performance index:

Festival class	City classes covered
Lower	C and B
Middle	A
Top	S and X

Upgrading a car past a class ceiling moves it up rather than making it dominant in the class below, and detuning to re-enter a lower class is legal here exactly as in the city. The player cannot buy their way out of a competitive field.