The are 2 types of Arcade systems for vB:
IBProArcade (
https://vborg.vbsupport.ru/forumdisplay.php?f=170)
v3Arcade (
http://v3arcade.com)
For the chat, there are some hacks which support certain types of chats to be integrated in tzhe forums, but also hacks for IRC channel integration, just llok around.
For PMing new users, no hack is required, there is already a setting in the adminCP which lets you do so.