Hi im wondering if the catalac inverters on the 04 STI are different or the same as the 02/03 WRX?

 

FYI - Catalytic Converter.

 

they're all just catalytic converters...just air filters in the exhaust that make the car quieter and slower. but if your question is can they be removed? then yes. replace them with a downpipe eithier completely catless or with a high flow cat...