I'm looking at getting the NZXT Sentry 2.

I'll be OCing my 3570K to 4.5GHz for now, but would like some headroom for 5.0GHz in the future.
It's on an ASROCK Z77e ITX mobo in a Bitfenix Prodigy.
Cooling using the XSPC Raystorm 750 RX240.

Question is, what extra fans do I need, if any for this setup? Or should I be replacing some of the stock fans with Cougar Vortex etc? I want my setup to be as quiet as possible.

Can I use the fan controller to control the pump speed of the Raystorm?

What are the benefits of using a fan controller with regards to silencing my system as much as possible?