Kyle, one more thing... are you sure you're up to building an upper? And have the proper tools?
I'd recommend buying an upper already factory built or by a vendor you trust. If you go with Sun Devil you are limited somewhat since you need someone to build on their stripped upper. This is the main reason I didn't go Sun Devil on one of my builds, of course if I ever complete the 80% SD lower I'll have the same decision to make.
Of course you're not locked in to Sun Devil (other than cosmetic reasons) so you can buy from any good vendor. Put a lot of thought in to what you want and what you need before buying anything. Barrel length, gas system length, barrel profile, twist rate, rails/handguards, sights, etc. I would use a BCM or Daniel Defense 16" midlength 1:7" as a straw man right now. See if it works out for you, throw rocks at the man, see if he keeps standing or gets knocked down and build him back up to your own specs.