How should i cool my pc?

Solution
You don't need more than a single 120/140 mm intake fan and another 120/140 mm exhaust fan. If you were to run two 270xs or you had a GPU with a much higher TDP, then it would be considerable to get more fans or different cooling solutions.

The fans included are more than sufficient most of the times, unless you live in a subtropic or tropic country, where heat rises high during the day.
You don't need more than a single 120/140 mm intake fan and another 120/140 mm exhaust fan. If you were to run two 270xs or you had a GPU with a much higher TDP, then it would be considerable to get more fans or different cooling solutions.

The fans included are more than sufficient most of the times, unless you live in a subtropic or tropic country, where heat rises high during the day.
 
Solution