The answers to all your questions can be found using the search function of these forums -- more precisely by using "advanced search."
3.92 works with some hacked drives, doesn't work with others. The only definitive workaround that has been found is if your drive happens to be a Samsung, in which case see:
http://forum.phathack.com/index.php/topic,1581.0.html3.76 works with all hacked drives, as far as I can recall.
Yes, the head unit setup does not work because the software is attempting to connect to servers that no longer exist. As long as you have installed the correct firmware on your DMS (which can be done using the Phathack DMS Tools from this site), that doesn't matter anyway.
You can change the firmware settings on the DMS from within the Phatnoise software (tools/options/DMS firmware-plugins). This includes the option to change the display from the default two digits to three digits.
If some voice prompts are not working, you can regenerate the voice prompts from within the Phatnoise software, which often corrects such problems.