SQL & PL/SQL

I have gone through various books and haven't found a definitive answer but the question is if there is any performance difference between a stored procedure with local procedures, functions, variables, etc. and a package with all that stuff. From what I have read, I conclude there isn't but I wanted an answer from somebody with a lot more experience than I have.

I understand the advantages of keeping common activities in packages and that is not the question. Instead, given a unique set of modular activities the choices are: create a bunch of stored procedures and functions that are dependent upon one another, passing all sorts of variables, on and on; create a stored procedure with the modules existing as local stored procedures, functions and variables (global to the local procedures in scope); create a package reflecting the same functionality as the stored procedure mentioned above.

I am arguing for the stored procedure vs. the package in design meetings but I don't have the breadth of experience to back up my claim. I was hoping for an expert opinion.

Thanks in advance.
Harold