Okay! I had my friend download it for me, and the file worked. Flashed well and booted and everything was normal, and I have just been through the experience of going backwards.
In order not to make this thread all about me and to share useful experience with people, I'll write my notes and observations.
Pay attention that this is for
Samsung Galaxy Ace (GT-S5830):
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First of all. Concerning the title of the topic of the thread:
If you were, like me, worried about CSC numbers and region-compatilibility, FORGET IT. It's a children's boogybear that does not exist. Just choose a firmware you want and install it. (Even though I'd still be wary of having what I heard people call a hardware-locked bootloader. In this case, be careful.)
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Second, about the ARABIC firmware itself:
It has a partially Arabized menus. (which i don't care about anyway, I use my phone in English), and it has full support of Arabic script in CONNECTED letters, which is what's missing in every other firmware.
SMS read and send in Arabic.
File names are recognized.
Contacts. Check.
Notes. Check.
Browsing and gmail. Check.
I didn't check the right-to-left alignment problem that every Arabic user complains about. I'm still busy frolicking about having script working.
MP3 tags were recognized in Music player, but NOT ALL OF THEM.
This might have something to do with what software I used to write the tags in, as different software use different encoding. (iTunes vs Windows' file property window)
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APPLICATIONS
The Arabic version is designed specifically for the United Arab Emirates. This is what it says in langauge choice.
The software comes with some Islamic software: a Quran reader, an Athan timer, and a Qibla direction applications... While I think this is cool, being a Muslim myself, I think this is a little inconsiderate for non-Muslim Arabs who prefer to have a choice. And I would install 3rd-party applications anyway because they are much better. The country/city settings for these 3 applications only list a small number of countries which Samsung must have considered "Islamic", which I think is racist, and does damange to the diversity of most countries, and to the global spread of Islam. So I'm a Muslim and I'm in the UK. I don't get my settings? etc.
I would certainly want to remove those applications and install my own. They're just not good
Most importantly, the firmware loses the ANDROID MARKET application! It has a "S-Android" (Samsung-Android) market application, and a "Slide ME / SAM 4.0" application which is another market/repository thing. I want the android market app which was on the European version of FroYo.
The "Samsung Apps" is also there, so notice that these 3 are not the same.
I want the Android Market back.
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FIRMWARE EXPERIENCE
You must know by now that the one-file package
S5830JPKC2 did not boot at all.
The multiple file package
S5830JPKA7, however, was a great faultless success.
I did not notice anything better when I updated from European 2.2.1 to the leaked 2.3.3. But as I have just downgraded to the Arabic 2.2.1, I notice there's a general slowness in responsivity which is not very pleasing. I cannot be sure it's a Version Build problem (all 2.2.1's are like that) or just the particular one that I have (only Arabic 2.2.1 is like that). It shouldn't be that big of a deal anyway.
As I rooted with SuperOneClick 1.9.1. The root worked, but it seems like I could not install many packages. Titanium Backup (installed from .APK file) worked, but upon restoration attempt gave me the message "Could not parse package". Same message came from S-ANDROID app upon trying to install Angry Birds.
I updated BusyBox from within Titanium Backup, and the restoration of Apps worked.
HOWEVER, not all my personal data was back. No Contacts. No SMS. No Notes. No Logs. Only Calendar was restored as far as I could tell.
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UI DIFFERENCES are scarce.
2.3.3 shows you the battery charge % on Lockscreen when charging.
2.3.3 LAGS when locking or unlcoking your phone, for about a second:
This is what happens:
When waking up, the pixels of the screen will wake up but the LED backlighting will lag for a second. The result is that you'll have to wait for that second.
When going to standby (push power button once) the LED will turn off immediate but the pixels will stay on for another second. Practically doesn't bother, but noteworthy as this is supposed to be an "update".
2.2.1 (I'm talking about the Arabic version now, as I did not pay any attention to this while I was on European 2.2.1) LAGS LIKE A SORRY B*ATCH while scanning Media is in progress. Makes me wonder what effect that has on multitasking, or tasking while having to read something from the phone's different memories.
Significantly, while users around the world complain about androids lack of support for different proxy settings, an ordeal that forces many people to root and install 3rd party applications, the update actually REMOVES any trace of proxy support the older version has.
2.2.1 has proxy host and port fields in the WIFI's Advanced Settings, which only affects the browser and not any other applications anyway.
2.3.3 has NOTHING of the like. They decided, in the update, that people's complaints are not worthy and that we'll do things our way no matter where people are using their phones.
For those who don't know what this is about: if you're in a corporate network (company, University, etc.) you'll have to enter their own proxy settings to use the net. %99.98 of corporates around the world proxify their networks. That means you can't use your phone in any of these. I for example, could not use it in university. What good is it without internet? The only solution is 3rd party applications. 3rd party applications will only do this with ROOT access. If you have no internet anyway, how the hell are you going to get root anyway? Ordeal!
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Conclusions:
Referring to the date of this post
1. If you're thinking whether you want to try the new 2.3.3 on your Samsugn Galaxy Ace, it's not worth it. Wait until there is a working root that is guaranteed and then update.
2. If you need Arabic on your phone, flash
S5830JPKA7 NOT
S5830JPKC2.That is the easiest method.
Using Arabization methods on my European 2.2.1 killed boot.
3. Do not worry about CSC and region compatibility. Firmwares install and flash regardless of where your phone has been designed for.
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That is now too much, I'll just shut up and post.
Thanks a lot wchryan for your help and support. You're the man.
to see that all my apps were disappeared.. All the disappeared apps were seeming greyed out in the application manager tool.. 
.. Its not even a month since i got the mobile and facing problem..
