Hey, Ernesto here, back after some personal issues that forced me to put in stand by my project. Now I'm focused on trying to finish the car conversion before the year end, as some might know, I'm doing a conversion from N/A to turbo in a 4g63 6 Bolt.

Already got all the hardware (lines, piping, bov). I know that I will need to replace the stock ECU as I'll be running different mix fuel ratios and force induction performance that the N/T ECU its not prepared for.

Somebody here have done this conversion before I think, so my doubts are:
If I purchase an GST/GSX ECU with the EPROM already serviced from ECMTuning, the wire harness connectors differs from the standard ECU in a Eclipse GS? If it's like that, what mods needs to be done in order to fit the new ECU?

Also if somebody here knows a good tuner based in Panama, Central America that can help me with the tuning process, I would appreciate a lot the information

In advance thanks for the help!

It's not so much a different ECU connector as it is additional wires going to it and the changes you have to make to the wiring harness in the engine bay to support the turbo engine. Your car being a 90 does add to the process, hopefully the new 6-bolt will use the 91+ style sensors and throttle body parts. Because it's a 90 you will need to know what year ECU you’re getting and make any changes that conversion requires.

This thread does a good job covering the general process. If you read it and have specific questions I'm sure we can find you some answers.