Took me a few days to finally decide to try it out and i'm pleased to say it worked. Thanks a million guys.
Just a few notes though on the route that I took:
I downloaded the firmware using the link you provided. No matter how much I tried, I got one zip file with 4 files inside. The PIT, Modem, PDA and CSC files.
I also used the method detailed in the GT-9100 upgrade guide from SAMMOBILE dotcom.
Checked the debugging option in the app setup.
I checked the three options - Repartition, AutoReboot and F.Reset Time in ODIN
I included all 4 files in the ODIN file paths.
Clicked on START (after doing download mode and connecting via usb)
Device rebooted, now using Android 4.0.4. Contacts and other stuff were wiped as expected so I just restored em using Kies.