According to the forums on Club3g, the tactrix cable cannot communicate with the 2000 Eclipse computers. The guy who makes the definition files says that the ECU in the 2000 has a different processor that does not support the cable reflashing. There has even been a market for swapping ECUs up to the 2k1+ so the 2k drivers can use the cable.
However, the mitsubishitechinfo.com site says all mitsubishi ecus from 98 up except the 98 galant and the 420a powered eclipse from 1995-99 support the same protocol for reflashing. While the mitsubishi
The 2000 ECU uses ISO 9141-2 as its diagnostic communication protocol and is included as a aflashable application by mitsubishi.
According to the tactrix web site the cable should be supported by all ISO 9141-2 capable vehicles.
My 2000 mitsubishi eclipse does support the ISO 9141-2 protocol.
The ECU Edit software should be able to read my ROM, then I should be able to adapt a definition file by comparing the 2001 GT MT definition file and its ROM to my ROM. Both cars share the same engine, driveline, fuel control scheme and timing requirements. The lookup tables should be very similar if not identical. My plan, as soon as someone verifies that the cable can be used to pull the ROM file out is to find the ignition map in the 2k1 ROM file then search for parts of it that i know will be identical{the most advance the ECU will ever use is 44 degrees in both, the fuel map will always be 14.7 during the closed loop efficiency based RPM and load points, the rev limit is 6510 no matter what[6200 according to mitsubishitechinfo.com]} This shouldnt really be as difficult as they make it sound.