Integrated to drive PSB Imagine T's in large room

Trying to make the jump from Denon gear to HiFi. I'll be adding a REL sub soon to the Imagine Towers (4ohm) for a 2.1 setup. Budget is around $1K (or slighly over) used and I'm not sure how to wade through all the options with good reviews, including:

- Bel Canto s300
- Naim 5i
- Sim Audio i5
- Creek Destiny
- Plinius 8100
- others?

I've read many posts that PSB need lots of power to "open up", which makes me wonder if the Naim at 50w (into 8ohms) is enough power?

My living room is 16.5' x 16.5' with 12 ft ceilings and opens via a large archway to the dining room of the same dimensions for a total of 6,500 ft cu. Will be 60% music / 40% HT, and I listen to equal parts classical, jazz, rock.

Not sure about preference for neutral vs. warm, but the Denon receiver driving the Imagines sounded too bright in my room. Large 3D soundstage is high priority.

Thanks!