EV FSA in a new site?

Hi,

I will implement very big FSA environment to existing exch. mbx archiving environment .(apparoximately 30 windows file server target will be archive)

Now i am designing new topology.

Customer dont want to use sis with existing exchange environemt and FSA.

They want to isolated system.

I think that creating new site and use new sql new polies and new stores  etc..

so customer will have 2 different site (for exch and FSA )

Other option is ,use same sql ,same directory db, use same site, but create different VS, index ,policies...

what is your recommendations?

You have any big EXCH and FSA environment running on different sites?

thanks...