Problem Alienware aurora r3 upgrade

Hi guys, I have a question about the alienware aurora r3, I want to upgrade the motherboard to a Gigabyte H81M-S2H with a built in i7 4970 and 16gb of 1600mhz of ram for around 600 euro.
On another forum a person said he upgraded to an Asus 1150 Z97-pro gamer, or msi Z97M Gaming (microatx) I can't remember which one. But he said it fit with the lights on. The reason I want to upgrade is I can force windows 8,8.1, and 10.. but the r3 was primarily built for windows 7.. even though it was a 3k machine. No more updates past AO6 for the r3 which is a shame. Any help would be appreciated guys. Thanks...