Is this Define R4 Mod enough for 670 FTW SLI? Not enough? Overkill?

Hi, I am a big fan of the Define R4 and am trying to mod it for a SLI set up:

Goal is to maximize BF3 MP 1080p performance on a 120Hz ASUS VG278H while remaining quieter than the open air alternative such as Corsair 500R, CPU is i5-3570K, will OC CPU and GPU when necessary.

Here is the setup(second card coming in a month later):
Define R4 $109.99
EVGA 670 FTW $407.99
140mm fan 4X $28.7(Bottom intake,Side intake, Rear exhaust, top exhaust. ), 2 stock 140mm are 67 CFM/15-19dba(moving the original rear exhaust to front intake)
Fan type: XIGMATEK CLF-F1454 : 60CFM/16Dba

PH-TC14PE $75.00 (comes with a Y adapter for plugging in 2 fan in one Mobo header)
Total 621.68

2X Front intake,1X Bot intake goes to the fan controller, Side intake/Rear and Bottom exhaust goes to the Mobo header(2X 4 pin for Cooler & 1 fan, 2X 3pin for the other 2)

To explain the fan set up in more detail:

The 2 stock 140mm fan will be located at the front intake, 1 140mm intake mounted at the bottom infront of PSU(feeds the FTW's intake fan), 1 140mm intake on the side panel about level with the 2nd GPU's PCI slot(feed the second FTW), the exhaust fans are located at the rear and the top rear fan mount.

Total Fan CFM count, 2X 67 CFM +2X 60 CFM intake, 2X 60 CFM + 1/2 Blower GPU exhaust.

Mounted on a Standard length slim ATX board: ASRock Z77 Extreme 4(support SLI)
PSU Seasonic X850 Gold.

Reason I picked FTW is that its blower style make sure one GPU's exhaust won't heat up the other GPU, with Windforce/PE I might need a more open air case and a side exhaust fan to prevent their exhaust heating up each other & the rest of the Mobo.

So, Is this good enough? Not enough? Overkill? Please let me know.