[GSR]

gsr engines use a dual stage runner manifold design. long runners are active up until 5800rpm when the butterflies open for the short runers. this gives better midrange torque.

civic's use single runners, the secondaries wont open=slow after 5800rpm. yes you will lose power

theecu has to be for a manual tranny

obd1's usually make more power. they also dont use the 2nd o2 sensor so you can run a test pipe wit no CEL. if you plan to go hondata you will need obd1