[Exim] install from Metzler site

I am trying to do this:

apt-get install exim4-daemon-heavy

on a Debian 3.0 box. The trouble is that it wants to remove my current
install of Exim. I had a specially compiled install of Exim 4.30 in order
to employ some anti-spam tools. Will this mess up my current
installation of Exim 4.30?

Chris