I bought the new M4 Post Ban Upper with the Mini Y Comp. This upper receiver has been combined with a pre-ban Colt SP 1 Lower receiver. The Mini Y comp is fine for controlling muzzle rise, but is noisy as the devil. What are the legal issues of having Bushmaster remove the Mini Y Comp and installing the 4 1/2 inch CAR 15/M177 "Original Flash Suppressor"? It's longer than the Mini Y so it meets the 16" law. Is this kind of suppressor less noisy than the Mini Y Comp? If so, is it compatible with the new M4 post ban barrel?