I always resort to one site for stats on high useage.
Stratics.com is probably the busiest W3T site around at this point. They have an average of 400-500+ users online at the same time. To handle this type of load they are running 2 servers, one for mysql and one for the scripts and html, though I'm not sure of the server specs.
It's possible to do the import under the PERL version and then switch to the PHP version. The import script only works with mysql and perl so this would actually be the path you would take.
I don't do installs myself but there are several that do installs. You can look in the installers forum or in the resource center.