Question [Q] Unlocking BL - need clarification


I am going to unlock my Arc S BL. I read many here, but need some clarifications:

My goal is to have XUHD 5.0.1 with suggested kernel (Lupus). Right now I have XUHD 3 (with mod), phone is rooted (I did it somehow). It got slow and buggy after a while, so I need to refresh it totally.


1. Unlock BL using SE Bootloader Unlocking v1.6 by quangnhut123 (seems easier for a newbie than "sony" way, not mentioning the test point one).

2. Using the same tool flash LuPuS Kernel Stock.

Now to be confirmed: All I have to do is to enter IMEI and select file LuPuS_anzu_Stock-iCsv16-full.img. Done?
What would I get after that? Shell I turn on the phone as usual (and it is supposed to run as normal, maybe fresh)?
Should I remove my SD card while doing steps 1-2? Is the contentt of the SD card erased after the process?
Gaps - totally new to me - should I do something with them?

3. Flash the ROM. Well I did it earlies and it worked, so I believe when I will get confirmatoion of above I might succeed.

To be confirmed: to "make phone as new" - what pratition should I wipe? I am going to backup everything possible earlier.
I would like to add my own ringtone. How to do that? (I was told it can be done after installing ROM - via CWM - need suggestions...)

Do I miss something? Do I have to check anything before I start (dont want to finish with not working device...)

Any help would be VERY appreciated.

big thanks in advance.