The quality of the Arx drivers and crossover is higher than those used in the P363....so, unless Jon Lane botched the x-over (not gonna happen), they are going to have more refinement and equal/better performance.
I am biased, but I have over 200 listening hours on the Arx A3 towers in my system. I only have about 6 hours on the Infiniti P362 towers (the 363's predecessor). The A3 sounded a lot more refined with lower listener fatigue to boot. The 362's sounded shrill to me when pushed hard by my Arcam AVR300.
Edited by BufordTJustice - 6/21/12 at 11:47pm