Hi James,
The software is avaiable from out web site under old versions. It is a bit hard to tell what version is actually installed in the ECU so it is best to just download the last version, when you try to connect to the ECU it will tell you if there is a mismatch and what version you need.
All MoTeC dealers will be able to get you a PCI cable. if you laptop does not have a serial port you will need a USB to serial adaptor as well. It is probably best to instal the current version of M4 software as well so that you have the latest communications software, do this after you have insatlled the M8 software.
If you email me at
mark.mccoy@motec.com.au I should be able to find a wiring diagram for an M48 which should be of help, there were not many M8s put on Stis but it will work.