99 mitsubishi eclipse with infiniti radio

Strange. In my 97 GSX all I had to do was run additional wire for the front channels to under the passenger seat to tie into the factory dash tweeters. I didn't use a DIN to RCA cable. Rest of the wiring was at the connector behind the radio. Never bypassed the amp, just tied into the factory tweeters at the amp. Maybe it changed between 97 and 99... If it is working as is, by all means leave it alone. Got me curious now. I believe I unplugged the factory amp, added the tweeter wiring and that was it. Heck its been 10 years since I installed the system in that car. At the time I got all the info from the DSM Forums. Something was funny about that stock system, like the Infinity amp was in parallel to the 4 speakers and fed the tweeters separately. I do know the front channels were less then 4 ohms after tying into the tweeters and at high volumes for extended periods I was overheating my old Kenwood headunit.