That depends on what you want. Do you want Atmos or richer bass, mids and treble?

Depends on what you want to achieve. Better bass or the possibility for Dolby Atmos?

My personal choice would be to add the Sub-Mini. I prefer the much improved Bass tones compared to hearing what would be pseudo height channel audio available on some audio sources.

The Beam gen 2 (is an awesome soundbar, but) is not a huge leap over the gen 1. The dialogue is better, but I didn’t have an issue with gen 1. I wanted the Beam Gen 2 for atmos music, and it does a nice job at that. The most excitement I got from replacing the gen 1 with gen 2 was that I could move the gen 1 to the master bedroom. I now have the arc and moved the gen 2 to the master. The most noticeable short term upgrade with a “wow” effect would probably be the sub mini. It should really add some depth to the beam. The nice thing is that you can eventually upgrade the beam gen 1. I don’t think you’ll be disappointed with whichever choice you make.