Corsair AX750 Gold PSU

Hi all,

Recently I built a gaming PC  

Here is my specifications;

Core i7 3770k ivy bridge
Asus Sabertooth Z77 motherboard
Corsair 8GB Dual Channel DDR3 Memory Kit
Corsair Force3 120GB SATA 6Gbps SSD
Barracuda 2TB 7200RPM SATA 6Gbps
LG 22x DVD-RW
Corsair AX750 750W 80+ Gold Modular
Corsair H80 Liquid cooler (CPU Cooler)
Coolermaster Elite 370 with 4 x 120mm fans (Casing) http://www.coolermaster.com/product.php?product_id=6656...

Still I haven't decided which GPU to buy. Ideally it would be an Nvidia Card. I wish to make a 2 way SLI system. Therefore, I'm waiting until GPU prices gets down with the arrival of GTX700 series. I would like to SLI two GTX670s or GTX680s. Will my PSU be able to handle the load of this system. If not what is the best recommended SLI platform for my PSU. To be honest i don't want to take an older card so that if i can not build a SLI system with GTX670 or GTX680 i will go for a one Overclocked GTX680. All sorts of EVGA and Asus Direct CU II variants of GTX600 series available in my country. Please advice me.  

And I know that having a larger gaming case will provide good airflow to the system. But currently I'm happy with my current case which can accommodate two way SLI system. But I want to know whether having a SLI system in a non gaming, relatively small case will harm any PC component and its long term efficient functioning.

Please help...........