An overclock to 3GHz should be easily handled by the Ultra 120. However looking at the motherboard layout and the fact that the Ultra 120 is quite large you may have difficulty fitting the mosfet heatsinks due to lack of space.
Also if you decide to change your graphics card for a more powerful one (which tend to be larger) then the northbridge heatsink may also be problematical so you'll need to bear that in mind.
That motherboard is designed for watercooling so may be overkill if you're going to use it with air cooling heatsinks.
The case is a reasonable size and appears to have a fan at front and rear so should provide adequate airflow.