Hey, no problem. I'm still a learner as well. it's just that i've successfully rooted my phone with that guide. just offering some help here

1. yes, KL3 is a firmware, successor of KJ2. Something like version 2 and version 3. So far, KL3 is the latest firmware for msian sgs2 phone.
2. err, don't know the technical explanation but something like kernel is the main piece of software to run your phone/firmware. When u root a phone, u will root or modify your kernel, so u can install different OS or ROM or firmware. Like in the first method of rooting, that doomlord's method will root your kernel. But it doesnt work for most latest firmware, like kj3. I was on kl2, and it didn't work on mine, with the first method. So, i have to follow the second method, downloaded a rooted kernel (rooted by someone else), and replaced it with my stock kernel on my phone. After that, my phone will be so called rooted. Then you will have to install certain apps, as described on that manual, like superuser, etc.
3. After rooting your phone, u can choose to use back your existing firmware or you can flash a custom ROM. i use back my existing KL3 firmware. The reason i rooted my phone is to have freedom on accessing my files in my phone. I can backup data for some apps, which non-rooted phone can't do.
4/ yes, u have to download the ROM and flash it into your phone, just like how u will do it with the custom rom. You can either use odin on pc or mobile odin,app on your phone.

my 2 cents
Correct me if i'm wrong

This post has been edited by superkingkong: May 7 2012, 12:59 PM

If u follow the instruction explicitly, u won't go wrong

if something goes wrong, the worst i encountered was that my phone could not start, an image of the phone connects to computer was displayed. nothing works. I downloaded the wrong kernal. i9100 is not the same as i9100G .. my phone is i9100G. that time i was new.. very new .. Then, i downloaded the kl3 firmware from sam mobiles, connect my phone to pc and execute that file, within few minutes, my phone went back to original factory settings*.

rooting won't clear the data on your phone, but backup anyway, just in case something goes wrong. Not sure what is imei backup, i didn't do it.

if u can use/see superuser icon, that means your phone has been rooted. plus, if u can use ktools, etc, then u should be rooted. Another method for confirmation, if u launch terminal emulator app, you will get a blue screen with a $ prompt. Type "su" (without the quote". You should get a # prompt. That means you are rooted. If you don't get a # prompt, then you are not rooted.

Hope this helps

I was rooted as well. I did a OTA update. After the update, i'm still rooted. It didn't remove mine...

when i launch titanium backup pro, it says i'm rooted. i can use setcpu, mobile odin pro, ktool,, es file explorer with root access

well, i guess it's true also, like doing a clean install, to avoid any problem in between.... and when u have time

i'm just doing a quick test to see if OTA will wipe out the root access. I'll be going overseas later. Just wanna test it out. .. when i'm back later, i'll do a clean install, since i got the firmware downloaded from sammobile

DXLP6

new interfaces i like that i can delete notification one by one.

battery wise, i think A BIT poorer than gingerbread