Should I make use of CGI::Simple/CGI for the query string parsing? Or should I just pull the relevant code from the module and plop it into my own?
If all the searchengines your Module can work with use the default ?aap=blaat&boat=bloat way of encoding the URL's, you should use the CGI module as a module. The advantage is that when someune fixes a bug in CGI.pm, you don't need to manually fix that bug in your module too.