Finally got around to trying to connect the Sandstorm Piwik instance to my blog (hosted outside of Sandstorm and at my own hosting site). Unfortunately, the recommended Piwiki WordPress plugin didn’t seem to work. I suspect one too many token keys between the token key needed by Sandstorm to get into Sandstrom, and the Piwiki’s API key needed by the plugin to access Piwiks in Sandstorm. For some reason, the recommended Piwik WordPress plugin only allows you to connect to Piwiks via the api and not by cutting and pasting the tracking code. I’m going to give the plugin you suggested a try.