By the way - ALL semi-auto rifles that accept detachable magazines pertain to the SAW (Semiautomatic Assault Weapon) ban of '94.
On a post-ban Mini-14, you can legally add one "evil feature" as defined by the ban. Add a flash suppressor or a pistol-grip stock, but not both. Careful with the flash suppressors, because some of 'em come with built-in bayonette lugs, thus putting you over the limit.
Don't add a folding stock. Doing so would put you over the "evil feature" limit with the pistol grip counted as one and the folder counted as another.