[mod-security-users] mod-security resource usage?

[<deb...@sp...>]

I am trying to spec out a system to runs as a modsec appliance
providing IDS /IPS to multiple IIS websites some very heavily used

Can anyone thing be figures on process load, memory usage of 
modsecurity? 

Do people recommend apache 1.3 or 2 if 2 prefork variable or other?

thanks
Mat