i personally would not go lower than ET28 if 19x9.5 on this car.
ive seen ET22 and lower setups on the front and while they look okay diagnally from the back, from the front the tires just stick out too much like a tank or something unless you have a fairly large lip or body kit.
i just dont like tires sticking out the arches or hella flush a toilet look. that's all.
there is a reason why the offsets are so high on the stock and nismo wheels.