Australia’s Most Common Car Mods – Legal and Illegal Explained

Australia’s Most Common Car Mods – Legal and Illegal Explained

Modifying your car is a passion for many Aussie drivers, whether it's to boost performance, enhance aesthetics, or simply make your vehicle feel more personal. However, Australia has some of the strictest vehicle modification laws in the world. Not all mods are street-legal, and getting it wrong can mean hefty fines, failed rego checks, or even having your car defected.

In this ultimate guide, we’ll break down:

• What types of car mods are legal in Australia
• The most common illegal car modifications
• State-by-state legal variations
• How to ensure your mods pass inspection
• Top modifications Aussies are making in 2025
• And what happens if you get caught with illegal mods

Let’s hit the road.

1. Why Aussies Modify Their Cars

Australians love cars that stand out, work harder, or go further off-road. Car modifications are popular for several reasons:

• Performance: Increased horsepower, better suspension, or improved handling.
• Aesthetics: Changing rims, paintwork, lights, or body kits for unique looks.
• Utility: Roof racks, lift kits, bull bars, or tow packages for camping and trades.
• Technology Upgrades: Modern infotainment systems, reverse cameras, LED lighting.
• Resale or Pride: Enhancing your car’s image or value.

But the line between personalization and breaking the law is thin — especially with strict roadworthy rules in Australia.

2. Most Popular Legal Car Modifications in Australia (2025)

Here are the mods that are generally legal if installed correctly and don’t compromise safety:

a. Aftermarket Wheels and Tyres

You can upgrade your wheels and tyres, but they must stay within manufacturer tolerances.

• Legal as long as rolling diameter is within 15mm–25mm depending on state.
• Must not rub or interfere with brakes/suspension.

b. Window Tinting

• Legal limit for front side windows: 35% VLT (visible light transmission).
• Windscreen: Only upper 10% may have a tint strip.
• Rear windows may have darker tints in some states.

c. Suspension Upgrades (Mild)

• Up to 50mm lift without engineer certification (NSW, QLD, VIC).
• Must maintain factory rake and geometry.
• Legal kits include Bilstein, Ironman 4x4, or ARB Old Man Emu.

d. Bull Bars and Nudge Bars

• Must comply with ADR (Australian Design Rules).
• Should not protrude dangerously or obstruct headlights/airbags.

e. Roof Racks, Canopies, Trays

• Popular for tradies and adventurers.
• Must be securely mounted and not exceed maximum load limits.
• Legally acceptable when properly engineered.

f. LED Light Bars and Driving Lights

• Must not dazzle other drivers.
• Can only be used in rural/off-road areas.
• Wired with independent switch and indicator.

g. Exhaust Modifications (Within Limits)

• Upgrades allowed if below 90 dB(A) for most passenger vehicles.
• Must retain catalytic converters (if originally fitted).

h. Cold Air Intakes and ECU Tunes

• Legal if emissions-compliant and do not increase fuel pollution.
• ECU remaps acceptable if tuned for road use (not racing).

3. Common Illegal Car Modifications in Australia

Modding your car the wrong way can result in a defect notice or a voided insurance policy. Here are the big no-nos:

a. Excessive Suspension Lifts or Drops

• More than 50mm lift or drop requires engineering certification.
• Slammed vehicles can cause unsafe handling and fail rego checks.

b. Underglow or Neon Lights

• Illegal if used while driving on public roads.
• May be allowed in car shows or private property only.

c. Loud Exhausts (Over 90dB)

• Police routinely issue defects for loud exhausts.
• Excessive backfiring or crackle tunes can also result in fines.

d. Pod Filters Without Air Boxes

• Exposed filters often illegal due to pollution and intake rules.

e. Turbo or Supercharger Conversions

• Must be engineered and emissions tested.
• Illegal without approval, especially on NA (naturally aspirated) cars.

f. Engine Swaps

• Not illegal outright, but require full engineering certification.
• Must meet ADR and be from the same vehicle class.

g. Non-Compliant Wheels and Tyres

• Excessive poke, stretched tyres, or rolling diameter variations are illegal.
• May cause unsafe handling or void ABS calibration.

h. Brake Light Tinting or Covering

• Illegal to alter light visibility.
• Smoked taillights and blacked-out indicators can result in fines.

4. State-by-State Variation in Car Mod Laws

New South Wales (NSW)

• One of the strictest states.
• Engineers required for suspension lifts beyond 50mm.
• Annual safety checks (eSafety/rego).

Victoria (VIC)

• Roadworthy Certificate (RWC) required for resale or rego transfers.
• Modifications must comply with VASS (Vehicle Assessment Signatory Scheme).

Queensland (QLD)

• Allows more flexibility with lift kits via LS11 codes.
• Police frequently conduct roadside checks in SEQ areas.

Western Australia (WA)

• Slightly relaxed laws but engineering still required for major mods.
• High penalty for illegal lighting or emissions tampering.

South Australia (SA)

• Accepts some interstate engineering certifications.
• Focused heavily on emissions and road noise.

Tasmania, ACT, NT

• Generally follow national ADRs.
• Some states allow more leniency for recreational vehicles.

5. How to Know If a Mod Is Legal?

Before modding your car:

• Check State Transport Website: Every state has a gov page detailing ADR compliance and accepted modifications.
• Use an Engineer: For major mods, consult a certified vehicle engineer.
• Ask Your Mechanic or Rego Inspector: They know what will pass or fail.
• Refer to Vehicle Standards Bulletin 14 (VSB 14): Australia's national modification guideline.

6. Popular Aussie Car Mods in 2025

a. 4x4 Lift Kits and Snorkels

• Off-roaders love suspension upgrades, snorkels, bash plates, and tow kits.

b. Aftermarket Infotainment Systems

• Touchscreens with Apple CarPlay, Android Auto, and reverse cams.

c. Performance Tuning

• ECU re-mapping for turbocharged vehicles is gaining popularity (especially in Golf GTIs, WRX, Hilux).

d. Cosmetic Wraps

• Matte black, chrome delete, or custom decals – legal and reversible.

e. Dash Cams & Interior Lighting

• Dash cams are legal and recommended.
• Interior LED strips legal if not distracting.

7. Insurance Implications of Car Mods

Modifying your car doesn’t just affect legality — it impacts your insurance too:

• Undisclosed Mods Can Void Coverage: Even legal mods must be reported.
• Performance Mods = Higher Premiums: More power = more risk = more money.
• Aesthetic Mods May Be Fine: Wraps and lights are usually okay.
• Custom Mod Insurance: Some insurers offer policies for modded cars (e.g., Shannons, Enthusiast).

Always notify your insurer of any mod, legal or not. Don’t risk being left uninsured.

8. What Happens If You’re Caught With Illegal Mods?

If police or inspection officers find illegal mods:

• You may receive a defect notice or canary sticker (yellow label).
• You’ll be forced to return to stock and re-pass inspection.
• In some cases, your car may be grounded on the spot (especially for safety breaches).
• Fines range from $300 to $3000, depending on the offence and state.
• Repeat offenders may face vehicle seizure or rego cancellation.

9. How to Stay Legal and Stylish

You can mod your car and stay compliant with Aussie laws. Here’s how:

• Stick to bolt-on, ADR-approved components.
• Avoid anything that affects emissions, noise, safety systems, or structure.
• Get certified for engine swaps, boost upgrades, or chassis changes.
• Join modding communities that focus on legal builds — they often share advice and engineer contacts.
• Keep documentation for all work done — parts receipts, engineering certificates, etc.

10. Future of Car Modding in Australia (2025 and Beyond)

With the rise of EVs, hybrids, and ADAS (Advanced Driver Assistance Systems), the car modding world is evolving:

• Software Mods: ECU tunes may be replaced with app-based mods.
• Electric Mods: Swapping battery modules or motors — still mostly illegal.
• ADAS Tweaks: Modifying sensors or radar systems (lane keep, auto brake) can result in automatic defects.
• EV Wraps & Interior Mods: Styling remains popular, especially for Tesla and BYD models.

Regulators are also getting stricter with new tech, so always check compliance before any EV modification.

Final Thoughts

Modding cars is part of Aussie car culture — from Utes with lift kits to hatchbacks with wide-body kits. But with strict state rules and changing technology, every modification needs to be made smartly.

✅ Stay legal
✅ Stay insured
✅ Stay safe

Before you touch that suspension or swap in a turbo, read the rules — and enjoy the journey.