Although the 7900 has an excellent power supply and is able to protect itself in extreme conditions the idea of protecting it further by using some sort of protection from lightning strikes nearby is a sound one. I have all my equipment powered by APC H-15 and every time they function in a storm I remember why I got them. The Panamax units you have appear to be big enough to power the 7900 at maximum output conditions which I would think would challenge your hearing before challenging the amp.
_________________________
Music system
Model 990/7500/Magnepan 1.6 QRs/Technics SL1200 MK2/Aperion S-12 Subwoofer/OWA3/Sony NS75H DVD
APC H15 Power Conditioner

TV System
Large Advent Loudspeakers/ Polk center/Monoprice surrounds/Panasonic Viera 42 inch/Onkyo HT-RC260/Sony BDP S590/Directv


Home Theater System
Onkyo PR-SC886/Outlaw 7125 Klipsch RF-82 L/R,RC-62 center, RB-35 SR/SL, BENQ HT1075, Outlaw LFM1-EX/OPPO BDP-83/Directv
Harmony ONE
Blue Jeans and Monoprice interconnects
APC H15 Power Conditioner