Got both versions installed...should I remove CS4?
Whether you should will depend on whether you have already moved all your work to CS&, updated your plug-ins and made sure your hardware like scanners or printers works with CS6. If that is the case, you can remove CS4, but be aware that you may have to reinstall CS6 again, because unknowingly the CS4 uninstall may remove shared components that it thinks belong to it while in fact they are updated already for CS6.
Mylenium