I'm thinking of going with this BCM upper http://www.bravocompanyusa.com/BCM-M16-Government-20-Upper-Receiver-Group-p/bcm-urg-gov-20.htm and with a standard BCM lower. 1)I'd like to know what rail you suggest adding the naked upper I'm considering? ... And, are there any complications with mounting a rail to an upper with a fixed front site? 2)I'm pretty set on going with the 20" barrel. But if you guys have any other suggestions as to which direction I should take, feel free. I see that this upper has the chrome bore and chamber... are there any other important features I should be looking for? EDIT:3) How much more do Noveske ARs run than BCM?