Two 120mm Fans for exhaust are overkill. You are creating somewhat vacuum. Reduce it to one that will do the job just as good.
Since a vacuum is being created, the 80mm fan could barely do its job. Assuming that 80mm on the side is meant to cool down a vital component, it would merely cancel out the ‘vaccum effect’ with little effect of blowing air to the component.
For the PSU question, Asus website has a calculator for it.
http://support.asus.com/PowerSupplyC...Language=en-us
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NOTE: Suggestions are based on my perceptive. I could be erroneous. Therefore, no one has the right to criticize an individual other than rephrasing and or expressing his own annotations on the subject matter itself.
