Need a new drivetrain

Would like to pick your collective brains. Not literally…
I'm rebuilding my XC race bike and would like some sugestions. It's an Independent Fabs Deluxe hardtail. I found out the hard way that my frame was intended to use a drivetrain with a 48mm chainline. I used Shimano (50mm) for a few years and kept having ghost shift issues when using the middle ring up front and the 2 larger cogs in back (call it 2/1 and 2/2). Lots of chainsuck resulting in some chainstay damage.

I have plenty of experience tuning and building my own bikes, but finally took it in to my trusted LBS. They informed me it was a chainline issue. I called IF and they concur. The bike is at IF getting the chainstay fixed up and the frame repainted.

So here's the $64K question:
If you wanted to use the best race oriented drivetrain, what non-Shimano setup would go with, and why?
Crankset, cassette, chain, and BB.
BTW, I weigh 185 with all my gear on. I am used to descending aggressively (used to DH) and I like to hammer up technical climbs.

I've been seriously considering the FSA K-FORCE MEGAEXO or the TEAM ISSUE MEGAEXO carbon crankset with the external BB, or the TEAM ISSUE ATB with ISIS BB.
What's the difference between the K-Force and the Team Issue MEGAEXO?
Anyone with feedback on external BB vs conventional?
I've read too many reviews about the unreliability with Race Face XC race oriented cranksets and BB's, so I'm a little wary of using a RF drivetrain.

I guess I should mention I am a SRAM man, so I already have the XO rear derailleur and shifters. I am going to stick with the Shimano XTR front derailleur since it is still the best FD on the market, IMO.