Hi Ellie,
After 3 days of driving my R34 GTT on the new Japanese spec Tein SS. The impression was very good, actually better than I expected. At first I was a bit skeptical about it, many ppls on forum and other sources were comparing the Jap Vs Aus spec Tein SS. But due to price difference, and Henry (from RMS motor recommendation) I chose the Jap spec and save about 400 dollars.
I cannot compare the Aus spec vs Jap spec as I have not driven the Aus spec one b4.
Luckily this long weekend in Adelaide I was able to take it out to some long journey outside Adelaide to test it out.
This is my impression of the Tein SS Jap spec:
The ride quality was much much better than my previous HKS one, as the HKS one was clearly design for Jap road, track uses.
The suspension was also very quiet going through huge potholes, rough surfaces.
The car seems to absorbs the uneven surfaces very well at both low and high speed (even better than the stock ones).
Handling was much better than the stock suspension, but not as sharp and light as the HKS one I have previously. But nevertheless, it is very sufficient for road usage even pushing the car very hard, it grips extremely well. Especially with uneven surface which the HKS seems to slip due to the car bouncing around a bit too much. At higher speed, you can tell much of the difference between the Tein SS (jap spec) than the stock, because it seems to makes the car's handling much more precise and responsive (although, not to the degree of the HKS one)
Ride height it remained the same as my previous setting on the HKS, which allows me to able to go into my house's driveway everytime without scrapping the front skirt.
So yeh, Ellie, I think you wont be dissapointed with the new suspension you ordered. Highly recommended for everyday usage, much much better than the stock ones. I will keep you up to date with new detail as I discover additional info.
Hope that helps, and would gladly like to hear your point of view when you get yours done
Cheers.