Modifying my Remington 870 questions

[markmohn]

Hello,
I have a 26" Remington 870. I want to set it up a little more for defensive use and having-a-cool-shotty use. I want to put a +2 mag extension, barrel that lines up with the end of that, left side sling mounts, and possibly a bayonet.

I'm well aware the bayonet is mostly useless, I just think it would look cool as fuck. I've ordered some Esstac shell cards to have on the side of the receiver, but that's it so far. What mag extender should I get; what barrel will line up with that; what bayonet attachment point (heard something about s&l bracket with a lug on it?). What sling attachment points?
Any advice is greatly appreciated.

[KayleighCollins]

You should replace your current 26-inch barrel with a 20-inch barrel. This barrel is not only more balanced with the extension, but also improves the ability to manipulate the gun in a confined space.