I've owned and/or used the following amps with my 2.5s with great success over the 7 1/2 years owning them:
Owned:
Air Tight ATM300
Cary Audio 572 SET monoblocks (don't buy these as the 572 tube has gone out of production and was quite unreliable)
Transcendent Sound 25wt OTL
Cary Audio 300B monoblocks
Mesa Baron tube amp
Used:
Accuphase 25wt S/S
Symphonic Sound 50wt S/S
Cary Audio CAD805 monblocks
Cary Audio 300SEI integrated
I have a smaller room than yours and everything except the Cary 300B drove them real loud. The Air Tight 300B sounds more powerful and open than the Carys but neither was able to properly control the bass. The 2.5s will put out ample bass but need at least 20 wts to do so.
Owned:
Air Tight ATM300
Cary Audio 572 SET monoblocks (don't buy these as the 572 tube has gone out of production and was quite unreliable)
Transcendent Sound 25wt OTL
Cary Audio 300B monoblocks
Mesa Baron tube amp
Used:
Accuphase 25wt S/S
Symphonic Sound 50wt S/S
Cary Audio CAD805 monblocks
Cary Audio 300SEI integrated
I have a smaller room than yours and everything except the Cary 300B drove them real loud. The Air Tight 300B sounds more powerful and open than the Carys but neither was able to properly control the bass. The 2.5s will put out ample bass but need at least 20 wts to do so.