Cerberusiam,
Do you know what exactly the Shift Enhanser does? I have one installed in the location you suggested and it works great. Just don't shut the truck off with it in race mode or it'll throw a code.
For some reason, (i think it was in the instructions) they said not to leave it in race mode when shutting down. I have not shut it down in race mode so I have thrown no code. Maybe Steven at DTT could enlighten us.