is there a correct way to edit

\includes\functions\featured.php

and

admin\includes\init_includes\init_special_funcs.php

i have in edited these files for Additional Multiple Featured Products to get it to work propely but was wondeing should these files be edited in an over ride folder or should the code added be in a file of its own

trying to make this module easier to install and dont want to over write files during the install if this is not the correct way

thanks
bryan