In MD, it can have a collapsible stock and flash suppressor and it's still not regulated because it's a dedicated 22LR rifle. You cannot receive the 25-rd magazine in MD, unless the FFL limits it to 20 rounds or less with a permanently epoxied-in stopper.
You can also pick up a M&P 15-22 in PA or VA. Thy might give you some crap about giving you the 25 round mag, but all they have to do is run the MD instant check. I picked up a MOE version in Gettysburg. Well, I would have if I owned any guns.
Magazines for the AR15-22 is the hardest thing to find. I have a bunch because I was shooting competitively with mine for almost 2 years. but I ended up selling two of my newest ones to one of my shooting buddies daughters because they could not find any in time for her first match. Still have 13 of various sizes from 10-32 rounds.