im now looking at a upper since my lower is complete(minus stock gettin it on payday). i really like the dissy look and so far the only complete upper that i have found that is close to what i want is the YHM black diamond specter. Yankee Hill AR-15 Specter XL Black Diamond Upper Assembly 5.56x45mm NATO 1 in 7" Twist 16" Fluted Barrel Chrome Lined with Diamond Quad Rail Free Float Handguard, Flip-Up Sights, Flash Hider Pre-Ban - MidwayUSA. now heres the questions part of this. what all parts are required for a upper? even tho the specter has most of what i want it doesnt have all of it ie. the bcg i want(bravo company or fail zero). and im also thinkin about a midlength gas system. can i even put a mid lenght on a 16in barrel? tryin to find out what all i would need to build a upper since i think i can build the one that i want for about the same price as i can a complete upper and get everything that i want on it. and i would like the experience. i know that you have to set the headspace and timing for the upper but i have many friends at work that all they do is work on our m-16's m4's and the m9's that we use. thanks for the help guys.