Whatever you choose, consider some sort of detachable scope mount. A home defense shotgun with a scope is slow when you're indoors (close quarters). You want to be able to engage your target quickly and even with a 1.75x power scope, it may be too cumbersome. Ask a buddy to show you ghost rings sights. It's very much like the aperture sights used on military rifles, only much larger. They're very quick and efficient. If you do go Ghost Rings, go factory. Remington silver solders theirs on. A major competitor glues it. Which would you prefer?
As to the gun, I like the Rem 11-87. If you get the Police model, it doesn't take too kindly to lower power loads. Also, stick with factory accessories like the extension tube. IMHO factory is stronger.
The Speedfeed stocks are OK, but I've never had to use them under real stressful conditions. I've been told by others that if you go running around and slam yourself on the ground (or bump the gun with enough force), a shell may pop out. Opps. Never had it happen to me though.