PDMWorks database strength

We have (7) Seats of Solidworks 2009. We have not startedusing PDMWorks yet as our company has been concerned that it is anentry level product that will not scale well as we grow to 20+users over the next few years.

Our equipment requires assemblies of more then 10,000 parts. Wehave very strong Windows 2003 servers and a fast managed networkdedicated to engineering.

I want to keep our PDM system simple, PDMEnterprise seems complexand overkill as we have one location and do not requirereplication. I have a few questions that may help give medirection:

1.) What type of performance hit will we see using PDMWorks .vs PDMEnterprise?
2.) Enterprise is SQL based, what database engine does PDMWorksuse?
3.) Are there maintenance jobs that can be run on PDMWorks to keepthe data healthy?
4.) How many users can be effective in a PDMWorks Vault?
5.) Is read-only access to Solidworks files in the vault by CAMusers reliable?
6.) What method exists to migrate data to PDM Enterprise in thefuture?
7.) Is a 64 bit server/workstation environment tested and reliable?
8.) Can a network backup (CA Arcserve) be successful if users arelogged into the vault?
9.) How do you restore a vault from a backup if it becomes corrupt?

Advice is appreciated.
SolidworksWorkgroup Pdm