If you go Pre ban you can always get your money back, and maybe more after the next shooting happens. I went pre ban as soon as i got my license cause i thought i was telling mass to go E'F themselves, but that has passed, so post ban config is ok with me at this point. i hardly ever shoot my prebans, pretty much collectables to me.
I think Collapsible stocks are a great convenience, fully extended versus completely collapsed makes a huge difference. I usually try what feels best and pin it were i like it. I think most of us Mass residents are so use to pinned stocks we've learned to live with it and think it's not a big deal. A collapsible stock on an SBR is even a greater convenience for conceal ability, if need be. Also having an adjustable stock lets you buy the shortest gun case possible for transport, 3-4 inches can make a big difference.
As far as muzzle devices go, i think comps make a massive noticeable difference, who cares about flash hiders, i'm not trying to hide from anyone or hunting at nite. I've since bought all my new rifles with pinned comps, the recoil and muzzle rise is nite and day from a flash hider on my pre bans.
Whether i had a pre ban or a post ban lower, i'm changing the muzzle device to a comp right off the bat. The stock for me is a non issue, i usually have the stock pinned only 2 holes from completely collapsed anyway, i like to be close to the charging handle and most of the weight towards my center of gravity, and if it's not comfortable for anyone else to shoot, thats to bad, it's my rifle.
