Hi,

we use a Tomcat-Application with xalan 2.7.1 to present our xml
documents to the user in HTML.

I read about XSLTC: It can have factor 10 of performance benefit.

In our xsl scripts we use java and xalan extensions.

given that the questions you're asking are specific to the Xalan
processor and may even involve more Java coding than XSLT writing,
the best place to ask for advice is probably xalan-j-users at
xml.apache.org.