You need a whole JDM or AUDM (japan domestic market or an australian domestic market) head and rocker cover as they are different shapes. You will probably also need a JDM/AUDM engine bay wiring loom and ECU.
Basically VTC is variable timing control and it is only on the intake cam (on the GA16DE). It is an oil pressure operated mechanism.
The only trouble with VTC is that while it increases your mid end torque, nissan has set it up electronically that it retards the intake cam's timing from about 5500rpm onwards, basically making a big drop off in power from about 5800rpm onwards. In otherwords, nissan is forcing you to change up a gear...
AFAIK there is only one company which has managed to make an ECU which actually benefits the VTC equipped GA16DE - and that is John Wolf Technology (JWT) in the USA. I believe in their ecu for the ga16de they have tweaked the VTC activation points to give the motor even stronger bottom end, mid range and fixed the high rpm power drop-off to an extent (the GA16DE head is capable of higher RPM than an SR20DE head but the GA bottom end is not as capable of high rpm as the SR series. Bloody nissan...)
GA's are also much quieter than SR's.
The GA in stock form though is hardly good for performance. It features a budget-buster cast iron block wih extremily thin cylinder walls - meaning there is no chance of boring the motor to larger capacity without a custom block... There is a GA18DE in the russian and south american market afaik, and it makes the same power and torque as an SR18DE. But various soruces tell me its a bit of a dog and doesnt like anything in excess of 5000rpm... So rule that out!
Go and check out Nissan Performance Mag (google it) and theur project sentras. The americans have just gone absolutely GA16DE crazy. Making big HP from these motors. They are really giving the SR boys a major shakeup. Hehe
The GA seems to be making more power per litre AND per PSI then the SR's...
Gotta love underestimated motors.
