Why is the weight of the Infinity Primus P363 such a factor? I'd consider 50 lbs to be a good thing for a small floorstander, and it has a lot going for it for being diminuitive while fully energizing your room and being devoid of cabinet resonances.
BTW, I think the WhatHiFi review chose poorly for the amplifier in their Aon test--an NAD D 3020, which is only 30 wpc. The symptoms they mentioned when trying to drive the Aons could easily be from running out of power. The Aons can absorb lots of power (200w) and play LOUD. With an 86 dB sensitivity, they should be able to put out nearly 110 dB (at one meter) with 200 watts input. That's loud, esp. in a 9x12 room. Your ceiling height doesn't make that much difference; it's the same volume as a 10 x 12 room with conventional 8' ceiling. This is the size of a typical kid's bedroom in a 3-bedroom house.
That review reveals more about successful amp-matching than speaker quality.
BTW, I think the WhatHiFi review chose poorly for the amplifier in their Aon test--an NAD D 3020, which is only 30 wpc. The symptoms they mentioned when trying to drive the Aons could easily be from running out of power. The Aons can absorb lots of power (200w) and play LOUD. With an 86 dB sensitivity, they should be able to put out nearly 110 dB (at one meter) with 200 watts input. That's loud, esp. in a 9x12 room. Your ceiling height doesn't make that much difference; it's the same volume as a 10 x 12 room with conventional 8' ceiling. This is the size of a typical kid's bedroom in a 3-bedroom house.
That review reveals more about successful amp-matching than speaker quality.