Loading 2nd database as read-only

[ElecMoHwk]

I've done some searching on the forums but haven't found anything really hitting this topic.
If I've missed something, please point me to a link if you have one. Thanks.

This issue is that the owner of the forum I'm helping out on, wants to load the vbulletin database of another site which he's acquired, as a read-only sub forum on his site. This would make the other sites old content searchable to his users, but not modifiable by them.

As far as I see it I have 2 options to get this done:

1) Load the 2nd database content into the exisiting database as a sub-forum. This seems pretty iffy and like it would require alot of db manipulation to avoid overwriting the current site's content and such.

2) Leave the 2 databases seperate, and use a sub-forum link on the current site to link into the other site's content, and leave the whole thing marked read-only, but accessible by non-logged in users, as non of the usersnames will match up with the other site's db (or, overwrite their user list with ours?)

Has anyone out there done anything like this?
What was your situation, and experience doing it?
Best practices for something like this?

Is there any method that is supported by the vBulletin team, or maybe just recommended as easiest/safest?

As always, thanks for all of the input in advance.