Editing PEAR packages

I wanted to makes some local edits to a PEAR package that I downloaded in
order to build some custom functionality into it.  What's the best way to
manage this process to ensure that I don't accidentally blow away any
changes if I update the package?  Should I just copy the entire package to
my own source repository, then use that directly instead of the PEAR
package?  And if I do it that way, is there an easy path to upgrade it?

Waynn