you need the CONVERSION harness to not wire anything.. It costs 350 or so whatever they say above. ******THERE ARE MANY HARNESSES :: GALANT EXTENSION/ECLIPSE AT EXTENSION WHICH ARE THE SAME, EVO 8 EXTENSION (JUST AN EXTENSION YOU WILL HAVE TO SPLICE THIS WITH THE GALANT EXTENSION TO RUN DUAL ECU.) AND A EVO 8 + GALANT/ECLIPSE CONVERSION HARNESS(THIS IS THE ONE THAT WILL REQUIRE THE LEAST AMOUNT OF WIRING IF ANY AND WILL BE MOSTLY PLUG AND PLAY).
You cannot run Tephras mods on every evo 8 ecu but 90% are compatible. Some evo 8 ecus have an intercooler sprayer. Not all roms can work with all ecus, some ecus can only use a small range of IDS and others are more supported for mods. What this means for you is EVOM is always creating patches allowing the stock evo 8 ecu to be manipulated much more than usual and you may or may not be able to use these patches. In reality its not a big a deal because you will have you the benefits from the ecu either way.