Charlie, I believe they have been more than helpful by telling the truth about the infinity subs. There are quite a few who has tried those subs, and are simply telling you what they have been through.
I think infinity subs are awesome (way better than mine), but every equipment/mftr is different... they hae their highs and lows. In the case of infinity, they do not like to be over-powered, whilst some subs take double, triple of their rated power.
They answered your question. DO not overpower it, else you risk the subs blowing.
Sony C90, 210 EQ
Seas 27TDF/C, RE XXX 6.5, custom xo (dyn 240GT sitting idle)
RF 60.2 amp
Soundstream picasso 1400.1D
Bass drive-by's are uncool.