I ended doing all the work myself, that was my first 6L80e conversion, i just remove the harness remove the 4L65E harness part and tcm,, converted the harness for the 6L80E and the trans worked just like that, the ecm was a E67 it has a stock calibration for the 4L65 and the 6L80e i installed has its own calibration, both computers have diferent VIN numbers and calibration from diferent cars and it worked perfectly, i just did some tuning on the TCM but was not necesary, then i converted a silverado to 6L80 and did 2 engine swap using L92 engines, all conversions was with diferent calibrations on ECM and TCM, i dont know if it was lucky but all the times it worked just fine, i didnt need to flash with tech2 same VIN number, (tech2 uses the VIN to install the calibration, if you need help or any question leet me know i will help i been learning cause i case a shop that mostly do engine swaps, and most of the time people like LS engine so i need to sttudy each time i work on an engine swap