Compare Filemaker 8 and 9

We already have server 8 (we bought it and got a free downgrade to
Server 5 to match our FMP 6 databases), but now we have to udate the FMP
6 databases.

I'm pretty sure I can buy FMP 9 seats and get a downgrade to 8 (and so
not have to upgrade the server 8). Question - what are the key
differences?

I In the FMP 9 demo I loved the map lookup tab. Is it in 8?
2. I understand Server 8 has features that they parsed out of server 9
basic. What are they.
3. Generally, are the tabs available in 8?

Thank sos much, could save me $600.

Peter