I currently have final cut studio 2 but instead of getting the upgrade my office got the full version of final cut studio 3. Will FCS 2 still be on my mac after I install 3 or will 3 overwrite 2?

3 will overwrite 2.

You can still do a clean install, if you just have the serial number of Final Cut Studio 2.
First use a free tool named FCS remover, and then install Final Cut Studio 3.

Little remark: LiveType dissapeared with Final Cut Studio 3 and merged with Motion.
So if you want to keep Livetype, you can do an upgrade and Livetype will still be on your computer.

Awesome, thanks Mathieu