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
Hey guys , i am currently deciding if i should make a purchase on a r34 that was initially an NA R34 but is now running with gtr engine. I am currently worried that the gearbox is not changed and a NA gearbox wouldnt...