Savage 320 Accessory Rail

Hi all, new to the forum, new gun owner, but not new shooter. I recently purchased a Savage 320 as my primary home defense shotgun and so far, so good. I think they've taken care of their QC issues (fingers crossed). Took it to the range and it functioned flawlessly, no issues to report. I'm thinking about accessorizing it and among the mods I'd like to do is to 1. attach an accessory rail system on the receiver because I'd like to place a reflex sight on it. and 2. buy a more compact stock. 

Does anyone here own one and have you added a rail on the receiver? If so did you need to get it drilled and tapped? I've seen a saddle mount made for the Winchester 1300 and some people have reported some success with it, others said it needed a little bit of modification before they could achieve a good fit. 

Secondly, has anyone tried to attach a shorter stock?