The reason I went with the 980 instead of the 970 is because I run triple monitor set-up in 1080p. Wanted to run the full 4gb. I bought the reference blower by EVGA. Yes I did remove the front fan and replaced it with a smaller one.
This is the fan I replaced it with:
http://www.frozencpu.com/products/1..._R126010BUAF.html?tl=g36c365s1625&id=sZ7UyJMh
This thing was a little hard to put in and took me a little bit of effort. Had to cable manage the power cable a little and had to partially pull out the front black bezel tab. ( you'll see it when you are putting the putting in the 980.). It kept getting caught on the tab. So I couldn't place it in all the way. That's what really help when I pushed the front black bezel forward a little.
I just put it in and runs all my games fine now. Batman Arkam knight can run triple monitor now for me in max settings. The game itself is still a little buggy till Rocksteady fixes it.
My specs:
Alienware X51 R2
Processor
Intel Core i7-4790 3.6 GHz
Memory
8 GB DDR3
Storage
1 TB 7200 RPM
500 GB SSD Samsung EVO
Optical Drive
Slot-Loading Dual Layer Blu-ray Reader (9.5 mm)
Graphics
Evga reference GTX 980
Power Supply
330W
Operating System
Windows 8.1 64-BiT