I'm want to build a ZZW30 that I can drive on public roads and take to the track and was thinking of fitting a 2ZZ-GE engine to this car. Can a 2ZZ be legally fitted to a registered W30? And fitted without the need for a modification certificate?
 
I had a look over the current regulations for light vehicle modifications that can be done without the need of a modification certificate. The rules only allow the fitment of a replacement non-performance engine with up to 20% more power. Therefore, a 2ZZ probably cannot be fitted to this car without at least a modification certificate. This is because the 2ZZ could be classified as a performance engine and the engine produces 40% more power than the 1ZZ-FE. An exception to this rule would be if the manufacturer fitted this engine to this car. However, I've done a quick internet search to see if there was a limited edition of the W30 with a 2ZZ and can't find anything. Has Toyota ever fitted a 2ZZ to this car?

Engine swap laws depend on state.

In Victoria it's based on the displacement, can't be more than a 20% increase.

Anything more requires an engineering certificate.

That's unusual because the document I got the regulations from is titled, "NATIONAL CODE OF PRACTICE for LIGHT VEHICLE CONSTRUCTION and MODIFICATION - SECTION LA ENGINE".
 
Anyway, it looks as if a 2ZZ can be legally fitted to a W30 and fitted without a modification certificate. This is because, page 23 of the above document seems to define a performance engine as, "... the fitting of a replacement engine with more than 20% greater mass and/or power output than engines offered by the vehicle’s first manufacturer as a standard or optional engines." And the US Toyota Corolla XRS had a de-tuned 2ZZ engine, that produced only 122 kW (https://cdn.dealereprocess.net/cdn/brochures/toyota/2006-corolla.pdf) which is less than a 20% power increase. A 20% power increase of the 1ZZ fitted to the W30 is 123 kW.
 
It looks like Toyota has re-mapped the ECU to de-tuned the 2ZZ for the Corolla XRS: https://www.youtube.com/watch?v=trUpmAz6UDI
 
Does anyone know where I could get more information as to how Toyota de-tuned the 2ZZ for the Corolla XRS?

In 2001 Toyota produced a limited run of the MR-S with a slightly tuned engine. The model was called the VM180 Zagato and had a MR-S chassis with redesigned bodywork panels. Also, the 1ZZ engine of the VM180 Zagato was tuned to produce 116 kW of power. Therefore, a 20% power increase would be 139 kW. Unfortunately, this is still less than the power output of 2ZZ fitted to the Australian Celica and the Corolla Sprotivo by only 2 kW.