Performance of Virtuals?

[Nik Martin]

I have a complex schema whose documents must be 'translated' into an xml format for regulatory reporting purposes.  The XML schema is quite different than my schema, in that there are complex types in the XML schema, as well as cryptic element names.  I am thinking about mapping my schema to the xml scheme using virtual properties, but want to see if there are any performance implications of this on my database, if the virtuals are only ever accessed by the reporting tools, not in normal DB read/write operations.  I can possibly have 75-80 virtual getters in the schema, that do nothing but return properties from the model.  There will be no virtual setters, and toObject and toJSON.virtuals is false, so they wont even show up in a normal document access.

Thoughts?