I will update this thread since I also installed win8.1 PRO.
Everything is working out of the box like a charm, except of course property drivers like Alienware FX, for which you need to install Command Center.
Nevertheless there are few bugs and incompatibilities:
1) Intel® Wireless WiFi 4965AGN will stop working with error code 10. Intel acknowledges this issue and card is classed as incompatible with Win8. Still there is a workaround, you have to disable n mode, it will work, but will crash with blue screens from time to time. Good news is that card is dirt cheap and is easily replaceable. I would suggest latest Atheros chips 928x instead of Intel's.
2) Winbond CIR device got some error code, same thing, no compatible drivers.
3) I can't switch between GPUs, OSD manager crushes each time I do, but I also think that my GTX 260M is faulty, so can someone check this for me?
Thats all for now
P.S. Can mods move this thread to legacy part to avoid confusion