Alienware Aurora Upgrade Decision...

I have been looking over the forum and several threads on 1366 vs 1155 vs 2011, but I have a unique situation. I currently have an Alienware Aurora R2, these specs:

i7 920
24GB 1333 Corsair memory
300GB Intel SSD/RAID 5 3TB
295 GTX Nvidia 

I want to upgrade the processor and the video card (another thread on this), but I think I want to deal with the CPU part first. I have the option to upgrade to a i7 980 for $589, and that would push me up to a six core with awesome crunching power. My other option is to upgrade the CPU, and mobo, but here is the problem. I want to keep my light functions on my system, so I would have to get a Alienware R4 (2011 socket) mobo, correct? This second option may pose a challenge, how to procure a R4 mobo, as they are rather new out.

So I can either..

a. Upgrade to a i7 980 = $589 and call it a day.
b. Upgrade to a i7 3930 = $600, and a Alienware mobo (who knows how much this could cost)
c: Upgrade to a i7 3930, forget the lights, and get a top shelf 2011 board. (Last ditch option)

Any input on this would be appreciated, thanks in advance.

A post-upgrade note, I will sell the 920 so that would recoup some cost of course.