So, Here's my current situation. I have built 2 16" barrel ARs and I don't need both. I want to only keep one, and really make that a nice one(better quality accessories) and sell the other. I plan to use this rifle for casual shooting/plinking, 3gun matches in the future, and HD/SHTF. The specs are: #1 Model 1 sales, heavy barrel 16" all flat top, UTG quad rail, YHM flip up front site, GG&G flip up rear site. Essential arms lower, standard CAR buttstock #2 DSA M4 style upper, UTG extended quad rail (the kind with cut out for site post), Flip up rear site, Magpul ACS stock. Essential arms lower Questions: 1. Which upper would be better in the long run, the M4 style or the all flattop heavy barrel? 2. Which style quad rail should i stick with, standard 7" or extended. 3. If I were to switch stocks, what is better quality the VLtor Emod stock, or the Magpul ACS? 4. What is the advantage of free float over 2 piece? 5. Are there any clear advantages to having different flash hiders? THey both have the standard A2, would the phantom, or the vortex be better? and why? 6. One gun has a M16 bolt carrier, the other has AR15. They are both legal, so would one be better to keep than the other? I am looking to get this quad rail if I keep the DSA upper or potentially a full length 12 or 13" rail and make the flatop more of dissapator. I just need suggestions/opinions...thanks... Wanna kill these ads? We can help!