okay i went to emissions testing and failed...they said that my ecu is not communicating with their program... i have a 1996 jspec gsr swap into my 1999 ek ...my ? is if i use a usdm ecu will this solve my problem??? i know that right now i only have 1 o2 sensor on the header... how many does a usdm gsr have? thanks in advance.

 

USDM GS-R has 2 O2's: 1 in front of the catalytic converter and one after.

You can get an OBD2 GS-R ECU, but then you've got to deal with the immobilizer.