Thanks for the props.
1) AFAIK, starting in 2005 GM went to splitting up the transmission computer from the engine computer instead of having it in one unit. In some applications, the transmission control module is actually located inside the transmission.
2) The LS4 is completely different from the 3800. I don't think there is anything on it that could be used on the 3800.
3) Yes that is an engine stand I used to hold the transmission. Works quite well.
-ryan