Hi guys
I will try to answer your questions, although all is explained nicely if you click on the link above.
First up you do not need to use Checkfus - this is however the best method of downloading the firmware and the quickest. It downloads Stock firmwares released by Samsung - in my case, I downloaded the Nordic one as this is the latest, released at the beginning of this month. Of course you can download directly from links provided at the above website but they will take an eternity to download, unless you pay for a premium download service - the file is over 337 MB in size. My previous firmware was a UK one - I9100XWKE7 (PDA) I9100CPWKD1 (CSC) - it was a CPW firmware (CarPhoneWarehouse) - it was the first ICS released one to enable me to upgrade from Gingerbread. I upgraded from GB to ICS 4.0.3 using Kies at that point in time.
So having downloaded the .zip file, extract the .tar.md5 file to somewhere on your PC. You may have to download the USB Drivers too because you will be placing your phone into "download mode" and at this stage, your PC needs to talk to it if you understand.
Next download Odin and open it on your PC.
Then power off your phone.
Press and hold down Volume Down + Home + Power buttons at the same time.
Press Volume Up button when warning prompt appears.
Download mode will then be loaded on your phone.
Connect USB cable to your phone and PC.
At PC bring up Odin.
Click on PDA.
Select the .tar.md5 file previously extracted.
Ensure all settings are as per the images in the above link - very clear
Click Start.
Wait until it finishes and PASS appears.
Remove USB cable from your phone only when you see green PASS in Odin.
When you restart your phone it may take a few minutes more than usual whilst it examines your apps and settings - you will see a progress bar and eventually you will be in your Home screen
That is pretty much all there is to it - make sure that your phone is fully charged before you start. The flashing process takes a few minutes together with a few moments longer for the initial reboot. All your apps and settings will be preserved as will your Homescreens etal.
As I have said Checkfus and the website in the links above only talk about Stock Firmwares and as such they are non-wipe. And you do NOT need to be rooted.
Finally, whether Kies will then subsequently infor you of future updates, that I am not sure about. Maybe somebody could answer that question please?
In my case I had a few minor problems, which led me to update. The phone is certainly faster and smoother now although I still get a heat issue when streaming videos - but this is only when I am charging at the same time. Have got used to playback without charging these days
Don't forget these firmwares may not be ones which will be released in your country - probably not. But this method gives you the ability to update to the latest firmwares without having to wait for Kies. If necessary, you could always revert back by selecting and downloading the latest firmware for your country, using Checkfus once more and going through the above procedure again - this will then allow Kies to notify you of future updates once more and allow you to play around with an updated firmware before you choose to revert back.
I hope this helps people.
I have been impressed with the ease of updating via this method, never really wishing to play around with custom firmwares etc.
roz