Ampli for Avalon Ascent mkII

Hi, I have Rega Planar, Treshold Fet 9, Spectral 90 and Avalon Ascent MkII. Is clear who necessity more power. I want change the Spectral 90 with 2 Spectral 80 (born mono). Any guy know very good the 90 and this 80? I not want missing anyone quality of '90.
Anto