You are able to change these, create new users inside of Piwik and so on.
<br />
== Security ==
<p style="color:#F00;" >
For piwik working correct, you have to edit the javascript-code it gives you by hand. Also, your hda has to be reachable from the websites you are tracking, like - if you want to track your website example.com, you need to forward HTTP-Traffic to your hda, regulary thats Port 80. This may open a big security-hole for your system. So - if you're not familiar with firewalls and security like setting up .htaccess and .htpasswd for your hda, you should consider to install the piwik at an server outside your LAN.</p>
Have a look :)