references as parameters

Hi,

This question _must_ have been asked before but I don't seem to find a
exact question(answer) right now.

I wanted to know what is the down side of passing parameters as
reference for data type >= 4 bytes.

For example:

funcRef(const int & i) or funcRef(const UINT & u)

How exactly is this worse than:

funcRef(const int i) or funcRef(const UINT u)

From what I know variables are created in each case, and each of four
bytes. But, type checking is better in first version than next
version. Am I correct?

Thanks,
Neel.