I own a Remington 870 Express Super Mag Synthetic 12 gauge. I’d like to get a better option for home defense. I could buy an 18" barrel (I’m seeing $200), mag extension, and stock. But as I’m pricing this out, I’m wondering if I’m just better off buying a new shotgun specifically designed for home defense. I paid $300 for the shotgun in 2007 (it’s in excellent condition).