Help building a gaming PC?

So should I make it so that the both fans are blowing wind out or in and can someone link me a video for installing fans with dust filters please.
 
fan filter needed for air intake.
The usual set up is air intake from front & side, then exhaust at back and top.
 
Thank you and would I notice a significant difference in games if I replace the i5 6500 with i5 6400 and 8gb with 16gb?
 
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