Putting fans in Corsair Carbide 400r?

Okay, so I have the Corsair Carbide 400r with the three stock case fans (Two 120mm in the front for intake and one 120mm fan for exhaust).

I just purchased 2 x 120mm Rosewill fans and I'm wondering how I should install them for the most efficient airflow possible.

Should I mount them both on the top for exhaust? Should I put one on the side for another intake and one on the top for exhaust? Should I switch out the front white LED fans for the new blue ones? Should I switch them up? I need advice...