BI Upgrade-Solution Manager, Web Dispatcher, IGS, Office 2003

We are planning on upgrading BW 3.1 to NW2004s BI. I would appreciate your valueable input on the following:

1. Is Solution Manager Mandatory for BI Upgrade? We don't have expertise in our team on this piece, so I was wondering if it is really required.

2. Currently, we have set up a server to run the Web Dispatcher so that public Internet users can access BW cubes via a secured custom intranet application. Do we need to do anythinng special with this piece during / after upgrade?

3. We have an IGS for Charts/Graphs in BW 3.1. Do we need to do anythinng special with this piece during / after upgrade?

4. I heard from some one that we need Office 2003 installed for all users? Could you clarify if this mandatory?

Thanks

Srini