server setup/testing performance

i'm looking for tools, like ab/siege/jmeter for web servers, to test
postgres performance.
not looking to resolve specific performance problems just to tune
configuration to get average/better performance for server than with
default installation.
i did use instructions from
http://wiki.postgresql.org/wiki/Performance_Optimization successfully
on existing installations but i would like to have a few scripts that
can test new postgres installation.
any suggestions?

Aljosa Mohorovic