Welcome Von Walrus
If you click on my sig you will reach the GWX website, there you will find the needed files for GWX & the 1.02 Patch.
You need a 'clean' SH3 + 1.4b as a base installation.
You need the:
GWX.exe Installer
GWX-1.bin
GWX-2.bin
GWX-3.bin
GWX-4.bin
GWX-5.bin
Put the above 6 files in a folder together and run the installer.
Then d/l the GWX 1.02 Patch and run it.
This will give you a standard GWX installation.
There are additional files if you are using SH3Cmdr and also a MD5 Compare program which allows you to check your downloaded files to make sure they are not corrupted.
Please note,
you will not be able to continue your current career.
Good luck.