I do understand the love of an A5 shotgun. I have my late Father's Savage Automatic which is a Browning Patent gun. It was made in the late '30s and has killed more game than all of my other guns combined. It will be passed down to my son in the near future. And a Light 12 Belguim A5 that has seen little use. Both are prized possesions and have places of honor in the safe.
That said if I had the Remington I would not modify it but would shoot it and enjoy it.
A dedicated home defense gun needs to be reliable if you are betting your life or the lives of your family on it working the first time every time. With a little time spent looking, a short barreled Rem. 870 Express or Mossy 500 can be found pretty reasonable priced. Owning two shotguns is much more fun than owning one.