xml::xslt and regexes

Question: What is the speediest tool to pull data from an xml feed that 
will only be a few hundred lines at most? Some regexes will be necessary.

Context:
I am playing with the google books data api. They provide a feed, which 
you can see an example of here:
http://code.google.com/apis/books/docs/gdata/developers_guide_protocol.html
(scroll about halfway down)

I can send search terms to the api and get back some information about 
the first three results in Google Book Search to integrate with our own 
search results. [Done] So in some cases the user may click through to 
GBS, and in others stay on our site. The GBS feed duplicates some tags, 
such as "dc:identifier" and the only way to distinguish them will be 
with a regex on the contents, or by noting tag order.

With the CPAN module XML::XSLT I am able to transform this pretty 
rapidly. I tried using XML::Twig, but it seemed too slow for this purpose.

However, XML::XSLT does not support regexes.

So I expect that I'll just have to transform the text as far as possible 
with XML::XSLT and the use Perl directly to finish the job.


-Chris