Calnin :
Check whether the motherboard is compatible with SLI.
You'll also need a bigger psu to support two graphics cards.
As for the pcie slots, it'll still be fine. There aren't that many cards in the market right now that'll fully bottleneck a 2.0 slot. The dual gpu cards and maybe the titan z or something might be the only few cards that'll be able to bottleneck a 2.0 x16 slot.
Ok, I have swapped the h80 for the 212 as reviews online have been quite good. Here is the new list of specs, thanks alot for all the help its really appreciated.
Computer Case NZXT Phantom 410 - Black & Orange
CPU Intel i7 4690K - (4 x 3.5 GHZ) OVERCLOCKED UPTO 4.4 GHZ - Haswell - FREE GRID 2 GAME
CPU Heatsink Coolermaster Hyper 212 Evo - Low Noise
Memory Corsair Vengeance 16GB PC3-12800 1600 MHz (2x8GB) - Lifetime Warranty (DDR3)
Graphics Card NVIDIA GeForce GTX 770 - 2 GB - (MSI) Twin Frozr OC - (PCI-E) (FREE Borderlands Game)
Motherboard Gigabyte Z97X-Gaming 5 (Intel Z97)
Sound Card Motherboard Integrated HD Sound
Networking Motherboard Integrated Ethernet Lan (Broadband Ready)
Power Supply Corsair 750W PSU - Low Noise
CPU Compound Standard CPU Compound Supplied With Heatsink
Case Fans Standard Fans Included With Case
Hard Drive #1 120GB Kingston SSD SATA-III, Read 450MB/s, Write 450MB/s - Silent
Hard Drive #2 1 TB Seagate (1000 GB) SATA-III HDD 7200 RPM 64MB
Optical Drive #1 Samsung 24x DVD/CD Re-Writer/Reader - Black - (SATA)
Operating System #1 Microsoft Windows 8.1 Standard 64 BIT (Genuine DVD & COA Included)
Upgraded the motherboard and added another 100watt's onto it.