I have a "post ban" neutered AR, and I'd like to "upgrade" it to a M4-type. With collapsable stock, flat-top upper and a M4-style barrel with flash supressor. I'd also like it to have a lightweight barrel. Now, where is a good place to get these parts without getting ripped off. I can install the M4-upper and stock myself.
Sounds as if ya have an A2 upper at present, FWIW, your here, simply saunter over to the Equipment Exchange, go to AR Parts "New" or "Used" and find both the upper ya like and the stock ya want, plop down your money and in a few days you'll have whatever your little heart desires delivered to your own front door......
Up top is a button called, INFORMATION which should help w/ the stock installation, the upper is no problem to mate to your lower.