Video cards questions

Apologies for the redundant posts <posted in configuration forum> however I was not sure which forum to post in. So I went with both.

227570
As some of you may know I placed my order on 12-22-08. It is know in stage 3. I have sent an Email and will follow up with a call first thing Monday regarding a change request with the video card selection. Basically I ordered 2x 280 Nvidia sli. My change would be for the 2x sli 295's. OR maybe the 2x 285's sli. I have seen some performance charts showing a 10% increase going from the 280 to the 285..? And a rather high jump going to the 295's sli especially at higher resolution. Particularly when maximizing settings at higher resolutions starting at 1920x1200. I also have seen power consumption ratios for the 295 based card at both idle & load. However nothing pertaining to the heat of the 295's or a comparison in performance for the 295's in SLI vs the 285's SLI or the 285's vs 280's in SLI. My questions are....

Would the 295's be problematic in sli (quad)? Is SLI problematic period?

Heat factor?

Power consumption? (copy of build to follow)

Basically advice, Maybe going with the 285's in sli over the 280's?

I know it is probably over kill as well as the bang for the buck argument. I would rather focus on performance,heat and stability issues.

as always thank you in advance....
Copy of Specifications:
Chassis Model: Cooler Master HAF 932
Exterior Finish: - Standard Factory Finish
Interior Finish: - Standard Factory Finish
Trim Accents: - Standard Factory Finish
Processor: Intel Core i7 Extreme Edition 965 3.2GHz (Quad Core) (Extreme Performance)
Motherboard: EVGA X58 3X SLI (Intel X58 Chipset) (Supports Triple SLI or CrossFire)
System Memory: 6GB DDR3 1600MHz Corsair Dominator DHX (High-Performance)
Power Supply: 1000W Corsair HX (Dual/Triple/Quad SLI Compatible)
Card Reader: Internal Digital Media Card Reader (Black)
Hard Drive Set 1: Operating System: 300GB Western Digital VelociRaptor (10K RPM) (16MB Cache) (Extreme Speed)
Set 1 Raid Options: - No Thanks
Hard Drive Set 2: Multimedia\Data: 500GB Western Digital (16MB Cache) (7200 RPM) (SATA)
Hard Drive Set 3: Backup\Misc.: 500GB Western Digital (16MB Cache) (7200 RPM) (SATA)
Optical Drive 1: DVD±R/RW/CD-R/RW (DVD Writer 20x / CD-Writer 48x) (LightScribe Edition)
Optical Drive 2: Blu-Ray Writer/Reader (Burn Blu-Ray discs and play them)
Internet Access: High Speed Network Port (Supports High-Speed Cable / DSL / Network Connections)
Video Card: 2x SLI Dual (NVIDIA GeForce GTX 280 1GB) (Includes PhysX Technology)
Add-on Card: - No Thanks
Sound Card: Integrated Motherboard Audio
Extreme Cooling: H20: Stage 3: High-Performance Liquid Chilled FrostBite System For CPU
Liquid Color:UV Blue: Medium Glowing Non-conductive Fluid (Requires H20: Stage 3 & UV Lighting)
Chassis Airflow: Upgrade Chassis With Zalman Performance Fans
Internal Lighting: Internal Chassis Lighting System (Blue)
Enhancements: - No Thanks
Chassis Mods: - No Thanks
Boost Processor: Yes, Overclock the processor as much as possible with complete stability
Boost Video Card: - No Thanks, Please do not overclock my video card(s)
Boost Memory: - No Thanks, Please do not overclock my memory
Tweak Windows: - No Thanks, Please do not tweak the services on the operating system
Windows OS: Microsoft Windows Vista Ultimate (64-Bit Edition) (For Enthusiasts)
Restore Kit: Digital Storm Specialized Recovery System (DVD Image Based)
Virus Protection: - No Thanks
Office: - No Thanks
Benchmarking: - No Thanks
Install/Test Game: - No Thanks
LCD Display: - No Thanks
Surge Shield: - No Thanks
Speakers: - No Thanks
Keyboard: - No Thanks
Mouse: - No Thanks
External Storage: - No Thanks
Exclusive T-Shirt: - No Thanks
Priority Build: - No Thanks
Warranty: 3 Year Platinum Care Extended Parts & Labor Warranty