Good build, I'd suggest going with a full length rail like YHM Diamond, a Spike Tactical SBR Fake Can, or a Real one if you can afford it. I call it the MOD4SB
Would also be nice if you can get a custom lower. I have my lowers made by tacticalmachining, and since I'm a 07 FFL holder I can have it manufactured with my name and logos and my own designs. I also find my customers like it when there's a full auto icon engraved seems to up the price a bit.