When ordering the sport I have 2 options:
#10208 15-22 sport
#10207 15-22 sport NJ... compliant

Can you have the 25 round mag pinned to 15 rounds?
(This has been done for pistols so your not stuck with 10 rounds)

Stock would have to be pinned as well. Does anybody know what else would have to be done for NJ?

#10207 comes with 10 round mags, are 15 round mags available that will still have last shot hold open?

Anybody in NJ with a 15-22, if so what did you order?

Found this very old thread discussing the Hell known as NJ
M&P 15-22 owners in NJ..

There was a post just a few days ago regarding 15 round NJ compliant magazines:

mags question

And the short is (for mags at least) is this:
http://smith-wessonforum.com/redirec...%2Findex15.htm

For the rifle, get the compliant rifle, it'll have everything done it needs to. That's why it's called compliant.

NJ owner of a 15/22 here. I concur with sithlord, buy the compliant version. Makes no sense to do otherwise. Re mags, refer to mags thread above. I added a post there you may find informative.

You have one option, if you live in NJ no one will sell you a non-compliant gun. Unless sent to a gunsmith to have stock pinned and muzzle brake pin/welded. I have over 25,000 rounds, only issue bolt jams open after last shot, but just read thread how to fix. great rifle easy to clean.