I'm not sure it really matters now adays... I mean, if you're going to target US users, by all means, have a US based server; but like say if your users are west coast USA and you rent east coast space it doesn't necessarily matter at this point.
We have a server that needs to have email sent via port 587 (the standard submission port) instead of port 25 (the smtp relay port) and I needed to know if there is a way to control what port email is sent out from by UBB Threads.
We're using UBB Threads 7.5.6.
Today they call you "crazy". Tomorrow they call you "ahead of your time".
It should follow whatever mail settings are defined by the webserver...
This really not something in ubb. Port numbers are set via whatever your host sets it at. If your able to edit your php.ini and host will allow 587 you can add or change the smtp_port setting. Ubb like others follow the php.ini file for mail.