Stag is good to go. That's what I have, and what I posted a picture of above.
About you saying you want a complete rifle, because you don't have time to assemble one. That's not what I was referring to.
If you buy a complete lower, and a complete upper, all you do is literally put put them together, and push the 2 pins in, and you have a complete rifle. I wasn't talking about actually building one from a parts kit.
For example, the one I have pictured above: I bought the lower, complete with stock. Then I bought the complete upper. Both are Stag. If I were to buy that same rifle, as a complete rifle, it would be $925. That's the price, straight from Stag's website.
But by buying the upper and lower separately, I only paid $759. So I saved $166 just by going that route. I could of saved more, but I wanted the Ace ARFX stock upgrade, so I paid a little more for it.
The only "assembly" required is as much as you would do to break the rifle down to clean it, and put it back together. Push 2 pins in, and you're done.
I was in your shoes a couple months ago. I was about ready to plop down over $900 for a Bushmaster at the local Gander Mountain. But after reading, and asking around, I found out how to save some money, and get exactly what I wanted.