My first post here! So I’m picking up a basically brand new Bren 805 carbine next week, just wondering what upgrades or add ons you guys would recommend? Thanks!
ALL of them.
I went M-lok (from KNS) all over my pistol. A good red dot, & a good sling (factory mounts are kinda funky. HK clips work best, but even then, they can still bind) are definite requirements. I also changed the charging handle to a KNS knurled model.
I also went with a Magpul handstop. In the pistol configuration at least, the lower the profile grip/handstop, the better.

I also added an INFORCE WML light to mine. And Troy sights.
Like I said - "ALL of them!"