NJ question about stock and buffer tube

[Ronbang]

I searched but didn't find anything. I live in nj
Question is this I have a sport ii and want to change the buttstock to whatever say a magpul fixed stock. Has to be fixed since I live in NJ. I've seen a lot of different answers to this.
The oem buttstock is pinned all the way out seems like. Can I just union the oem stock and then just put the magpul fixed stock on? Some people were saying the oem buffer tube on nj complient sport iis are longer...that on the fully extended stock it goes all the way out so if you unpinned it you get make it smaller.
So would I have to buy a new buffer tube also or no it's just a normal buffer tube pinned and I can just take it off and slide the new magpul fixed carbine stock on?
Thanks

 

[sgtsandman]

If memory serves, a fixed butt stock uses a longer buffer tube than a collapsible butt stock uses. So, if I'm right, you will need either a spacer or a different buffer to make the stock work.

 

[rtquig]

It is a different buffer tube and spring from the regular Sport II.

 

[Moe Mentum]

The fixed stock requires a medium tube, the tube on the sport II is the small tube. You have to replace the tube and the spring.