elgg and technology stack

hello guy i need help with understanding elgg and infrastructure. i have read http://learn.elgg.org/en/2.0/admin/performance.html and i understand but i need an experienced developer to tell me exactly how many users can elgg (in a vps with 2 CPU cores,

Operating System: CentOS 6 - 64 Bit
RAM: 2,048 MB
Space: 40 GB
Bandwidth: 2000 GB)handle(in a lay mans language preferably),and what is the preferred number of plugins to be activated in your elgg installation(20,30 or 40 plugins)...thanks would be much appreciated

Performance and Scalability

Performance and Scalability

If you've got a need for speed, this group is for you.