Thanks guys, currently Denso Tough Iridium plugs are installed in the car, i got these when the car was purchased. I don't know when they were installed by the last owner or are they compatible with Vitz or not. So, i m going to change them.
I visited few shops, NGK was the most recommended by the shopkeepers. So i thought to ask you guys.
@hassaan443 Can you share some Part or Serial no. of Denso plugs you are referring.