May also find yourself in trouble with authorities. It is illegal to modify/change any part of the engine combustion/exhaust/intake/fuel etc as you would be in breach of ADRs (Australian Design Rules) All vehicles manufactured on or after 1 January 1986 must comply with ADR 37 including:
•This category of vehicle may only be fitted with an ADR 37 or later complying engine - ie an engine designed to only operate on unleaded fuel), which incorporates all associated emission control components.
•Fitting an engine other than an original or optional engine requires approval from the Department of Planning, Transport and Infrastructure.
•No alterations to the engine's camshaft, inlet manifold, carburettor/fuel injectors, engine control unit or the catalytic converter or exhaust emission control standards are permitted.
•Airflow meters must not be disconnected.
•Modified or aftermarket plenum chambers or throttle bodies are not permitted.
•Extra or larger fuel injectors or variable fuel pressure regulators are not permitted.
•If the vehicle was originally fitted with a catalytic converter by the manufacturer, the vehicle must continue to operate with one.
and
Emission Control Laws.
Check with Authorities in your State