This question is fine. Don't worry about it.
While the Xbox mods work on the basis of replacing the BIOS, the PS2 mods patch the data that is transmitted around the board (the Enigmah Beta worked in a similar fashion). It patches the BIOS data, sends data when the PS2 expects to receive it from an original, etc.
Of the 3 mods, I highly recommend a Messiah2 for its incredible value,. Magic 3.1 tend to give some trouble (with DVD-Rs, DVD9s, and V7 consoles). The DMS3 v2.0 is a good chip, but it is sometimes very
picky about the installation (the installer must be meticulous), the flashability's usefullness has yet to be determined, and it has a high pricetag. The Messiah2, however, is very stable and inexpensive ($35 from http://www.foundmy.com
), plus I find the install to be much easier than the DMS3.