[masraum]

Text email messages take very little BW. I'd suspect that 400 messages over the course of 8 hours wouldn't warrant any extra BW over what you have now.

My company is a service provider of sorts. We have connections from our office to several different corporate offices for providing data (shared drives, email, intranet, etc...) as well as voice over IP. In most cases a T1 is not only sufficient, but probably overkill.

The only way that moving the email server would be a problem is if the emails regularly contained large attachments or there were much, much more than 400 messages a day.

How much junk mail do you get? That's the one other consideration.