[Xenon]

you can make it with a few db-querys:

if you have the same usergroupids then you can mak the "fast" way.

lets say the board which would become bigger has 2000 users (highest userid lets say 2499)

run this query in the exporter DB:
[SQL]UPDATE user SET userid=userid+2500[/sql]
[SQL]UPDATE userfield SET userid=userid+2500[/sql]

lets say the importing board has the highest forumid=10

in the exporter db run
[SQL]UPDATE forum SET forumid=forumid+10[/SQL]


lets say the importing board has 20000 threads (highest id=20000)
[SQL]UPDATE thread SET threadid=threadid+20000, postuserid=postuserid+2500[/SQL]
[SQL]UPDATE thread SET forumid=forumid+10[/SQL]

and to the posttable with highest postid=100000
[SQL]UPDATE post SET postid=postid+100000, threadid=threadid+20000, userid=userid+2500[/SQL]

then make a dump of the tables user, userfield,post, thread and forum and then upload it to the other db.

this must work, but be careful