PS2 Version Identifying

[Milkshake]

I've got a PS2 for my birthday and I know that it has been modified cus I can play cdr backup games, but first I have to boot up using DVDRegionX (no dongle).
I can also use this DVDRegionX to play DVD region 1 movie with success.
Please help me to identify what version of PS2 I have and what has been modified (what modchip used)? I feel very uncomfortable to unscrew the casing to find out what is inside but for your info it has 8 screws at the bottom.
All I know that it is a japan PS2 because when it is turned-on the screen is filled with unrecognizable japanese charactors.
I have been told that this PS2 was brought from HongKong.

Here are some Id numbers which may of help to you to identify the PS2 for me.

Model : SCPH-30000 (3-071-641-01)
s/n : J718xxxx (also on the box shows S01-718xxxx-L)
NTSC-J

Please help.

Thx in advance