freefloat RAS will prevent barrel wobble on an M4, just avoid using the front sling mount. Definately get a Free float one, though, as the TM RIS unit is very fragile and only adds to barrel wobble. My advice, for a nice, balanced AR is a vert grip, crane stock and reflex sight of one form or another. Keeps the weight even and lightens the front end up alot compared to AN/PEQ battery box. There's a reason why everyone and their dog is running this setup, it works and is very nice to handle.
Also check out a CASV, they are very nice, relatively cheap, and can fit a nice sized battery in it, freeing up stock choices that'll fit your personal needs/tastes.
And don't let these AK fans intimidate you, they're living in the past, where accuracy and range don't matter
(speaking from a real steel point of view)