I want to buy a new PSU for my PC

I want to buy a new PSU for my PC. i really want a Platinum rated PSU, and thinking of the Seasonic X-520. should be enough to power my system. but i'm worried that i cant mount it in my case. Seasonic tells to mount it when the air holes at the top, but are the cooling gonna be good enough, at the top of my case, can i use the one, or is it a bad idea?

CPU: AMD FX-8120 Black Edition (3.1 GHz Socket AM3+)

CPU Cooler: Corsair Hydro Series H80

RAM: Kingston 16GB DDR3 1600MHz (2x8) HyperX (Model: KHX16C10B1K2/16X)

Mainboard: ASUS CROSSHAIR V FORMULA-ZGraphic card: ASUS GeForce GTX 470


2 x Western Digital Velociraptor 300GB SATA in RAID 0

2 x Western Digital WD Black - 1TB in RAID 1

case: zalman z machine gt1000

Should be fine but to be sure you could get a psu with a fan.

so you recommend, that i go with something like the Seasonic Platinum 660? but will my system still be in the butter zone of the PSU?
at one point i also want to upgrade my graphics card, to one that performs equal, because it seems like this sures less power this days, what will happen there?

ever thought about the Lepa G650W 80+ gold? for $109



Nope i haven't, i really want a Platinum, but i do like, and vil keep it in minde. :)