Also, you can use

$ua->request($my_request);
[download]

instead of

$ua->get('http://site.com');
[download]

Then you can construct $my_request using http://search.cpan.org/perldoc?HTTP%3A%3ARequest and http://search.cpan.org/perldoc?HTTP%3A%3AMessage

HTTP::Request is inherited from HTTP::Message and HTTP::Message does have a method remove_header