Brother I emailed them a year ago right when I purchased my vitz. I asked them if it can work with JDM SCP-90. In reply their representative warned that they have never installed and tested it with JDM vitz. The circuit diagrams might vary and they do not take any responsibility of malfunction during driving or installation.
At that time I thought, if it fails, it will be a waste of money and may cause some other damages too. So I refrain from it.
Any hard and strong pakwheeler brother can try it :) Apni to himat nahi hoi company ka jawab sun ker. LoL.
Some good tech guy needs to compare circuit diagrams of EU version and JDM version of vitz. If they are dead same, I dont think there should be the issue. Note: I email this to the company and asked them help in diagram comparison. But this time they simply didnt reply 
By the way: I tried to compare the diagram myself too. but alas thanks to my intelligence, I failed miserably to understand many circuits
Hatsoff to zunny bhai if he has done it. Please do update us too after contacting with him. It would be a great add-on I will be among the first few to get that in :)
