I own D16A9 (European ZC) and wonder how can I easily increase air flow upgrading intake manifold. Shoul I bore it to 60mm or replace? What are suggestions? Is Y8 the best oportunity?

 

Are you talking about the intake manifold or the throttle body? You should get a larger throttle body for sure. Usually that is a "bottleneck" area. Your manifold should support a larger throttle body's increased air flow. If you do increase your throttle body size you should make sure the port into the manifold is the same size. (i.e. If the TB is 60mm, then the port size on the manifold should be opened to 60mm.)

Brian