The 11-87 barrel will fit on an 1100, but unless you have one of the very few, and rare, early 11-87 fore ends, the fore end will not fit properly on an 1100 with an 11-87 barrel. The barrel gas ring on the 11-87 barrel is longer than the standard 1100 one so the 1100 fore end will not slide on as far as it should to fit properly. I feel the gas seal collar is superfluous, but even without that the fore end still will not fit properly.
If you are having cycling issues with your 1100 with the original 2-3/4" barrel, the first thing I would do is reinstall the original action spring, especially if you did not replace it with a Remington spring. Then, #1 make sure the loads are 1-1/8 ounce field loads or stronger, #2 I recommend getting an old style Gas piston and piston seal. With the old style, they are two separate pieces that fit together on a bevel rather than one part snapping over the other. If you want to shoot less than 1-1/8th ounce loads, the odds are it will work fine with 7/8th ounce loads, but if it doesn't we can then tackle that.
The only differences that matter between an 1100 and an 11-87 are the barrel and the fore end. An 11-87 is only designed to function with 1-1/8 ounce field loads and greater, but there are ways around that. Many work fine with less, but that does you no good if yours is one of the ones that won't.
Why do you prefer the 11-87 barrel ?