K&N Cold air intake & Air Filter install

[kzam02]

I have a question regarding the K&N cold air intake and the air filter installation.
Do I need to install both? Since the cold air intake already has a filter at the end is that enough or you need to replace the stock air filter too.

The way I see it is that the stock air intake is a box and it connects to the airfilter box so I am assuming that it filters air through before getting into the chamber. If I am replacing the stock cold air intake and the K&N is not boxed in and from the pics that I see it just hangs outside in the open and I see that it's not being connected to the air filter box.

Do I still need the air filter or do I completely remove the airfilter housing and just having the cold air intake from K&N is enough instead of the air filter.

Please help!