Pass Labs upgrade?


Hi,
i am looking to hear from anyone that has/had the Pass Labs XA-60.8 amplifiers and upgraded to the Xa-100.8 amps. What was your experience like ? Was it worth the leap?
my speakers are pretty efficient @ 91 db but I am interested in the next model of Pass Labs for potential increase in overall dynamics.
128x128jb2455
any word on replacements for the XP-10 and XP-20, as they've been around 7-8 years now? 
I see that Don. I was thinking that with so many responders here having spoken to Nelson and Kent, since we are in  their 8-10 year timeframe, maybe they had some inside info...
I have and love the XP-20, but have found every new generation of Pass to be a significant upgrade