Spark Plug for 4AGE BT 20v engine is IK20.
For further information, u may refer this website
http://www.globaldenso.com/en/products/aftermarket/plug/basic_knowledge/heatrange/index.html
DOES ANYONE IN MALAYSIA HAVE USE THIS KIND OF TURBO...IT'S VERY POPULAR AMONG DA DSM TUNER/FAN IN US....I HAVE SEEN MY FRIEND USING THIS TURBO THIS TURBO AND HIS CAR RAN WELL...EASY TO LAUNCH DURING DRAG AND IT'S LOW...