You could buy that upper, probably shoot good ammo with at least minute of man accuracy.
I truly cannot say how it will perform, also you will need a BCG.
I would suggest getting a BCM upper
with BCG it will be around $700 and keep your build under $1k.
You will eventually upgrade components, so you should make sure you put the most money into the most expensive and important part now.
Because it will suck when you want more accuracy, and you realize you need to spend another $700+ to get a better upper.