The single biggest recommendation I have, is if you want a railed forend for flashlights or a grip pod (which I highly recommend) is go with a VLTOR VIS monolithic upper receiver. By the time you buy individual components for a railed forend and an upper receiver, you're in the same price range as buying this. The rail is prfectly aligned allowing scope mounting without a cantilevered mount. Also this system makes barrel installation a snap, it even comes with it's own barrel nut tool. About $550 gets you a midlength setup.
