Yes, ND3T-W58 is the latest model in the ND series. Really Japanese to English? I doubt that, but if it's possible you have one buyer for the software right here.
Do the front shocks have some sort of play in them? Rattling, did you check the condition of the ball joints and control arms? The ball joints on the Belta/Vitz are quite strong though they last a pretty long time.
I think he was referring to the rack and pinion. If you do go for used parts get them from a half-cut Belta/Vitz the parts for the suspension, steering are the same for both.
X is the standard specification model. G on the other hand is the top-of-the-line specification model.
No the G package isn't available for the 1.0L variant. Have a look at the original post at the beginning of the thread you will gain quite a bit of knowledge regarding the Toyota Belta from reading it.