Motherboard Overclock Cooling

[ADVgamer]

I want to overclock my "Gigabyte G1 Sniper Z97" motherboard and for that I need to buy a new cooler! I need help with something though... Should I be worried about my cooler not being a top down one?
I've been using the stock top down cooler up till now. I went to the store to get a new one(Ninja 3 Rev.B) but the guy said that I should get a top down cooler like the "Grand Kama Cross 2 rev.B" so that I have a fan cooling my motherboard as well as heat-pipes cooling my CPU...I don't know if I should trust him on that or not though!
What I want to know is:
If I overclock my CPU do I need a top down fan to cool my motherboard, or is it ok to get the Ninja 3 without worrying about my motherboards temps?

My case does not have any extra fans and the airflow goes from front to back!

 

[LucaFire]

I really don't think that you need to be worried too much over the heat of your mobo. If you're cooling the prime components that are producing heat (GPU and CPU, perhaps even the HDD or SSD) effectively, then the mobo should be relatively cool.