Which Sapphire 7970 to get?

[Piotrsama]

System Specifications:
I. Processor/CPU: AMD FX 8350
II. Current Graphics Card: 2x Radeon 5830
III. Display Resolution: 1080p
IV. PSU: NZXT Hale82 750W

Purchase Details:
I. Budget: Around $400 (not taking into account rebates or free games), but could push it a bit, if it's really worth it.
II. Any particular preferences Manufacturer[AMD], Brand[Sapphire]
III. Do you plan to have any Multi-GPU solutions? Not for now.
V. What are your needs for this GPU? Some gaming, and some mining.
VI. Do you plan on overclocking the card you intend to purchase? Yes, on air and stock HSF.

OK, which one should I get?
I'm not sure if the Vapor-X is an improvement over the other Sapphire HSF (Dual-X it's called?).
Tahiti XT1 or XT2 for Air OC?

$399.99
The "old" version of the Sapphire (I think it's the Tahiti XT1).
950 core, 1000 boost (5800 Mem)
http://www.newegg.com/Product/Produc...&SID=u00000687

$439.99
Or this 7970 Vapor-X Gigahertz edition? (Tahiti XT2?)
1000 core, 1050 boost (6000 Mem)
http://www.newegg.com/Product/Produc...82E16814202001

I could also consider a good 7950.

Thanks for your time!