how can I, make different forumdisplay?

[chephalonia]

for example I have this forumid strukture
1 parent (level 0)
-2 marketplace (this is a forum for sel and buy) (level 1)
--4 abc market place (level 2)
--5 xyz market place
-3 chat forum
--6 talk about abc
--7 talk about xyz

1. I want to make different forumdisplay for only forumid 2, how can I do that?
2. I have another custom script (different database) to put in forumid 2 too, better i use ajax or just iframe, or there is better one?

Can you help me? Thank you