Sounds like some custom shop work because the requirements of 5.45, 3 MOA, and M4 stock compatibility. You won't know if it shoots less than 3MOA until you shoot it or some guy tells you before you get it. Maybe find a guy who does custom work but, I hate to be the guy that says Krebs...
That's a lot of money though. I don't know who krebs is but, that's a cheap commie pos he's trying to off for $2000. I wouldn't spend that kind of money, it's like a fad at that point.
Why not an AR-15 they are so cheap!