Just pretty much echoing what everyone has said. I own the SVS PB12-ISD and it is a beast. It is plenty enough for me, more than plenty in fact, although I have a medium sized room. I have the volume/gain at 35% and small animals scurry away from the rumbling. Works well for rodent control. If that isn't enough, legend has it the Axiom EP 500/600 will drive off any livestock if you have any of those issues.
I have owned the HK 635 and found it to be a very capable receiver. Hard to find anything under $1000 USD "A" stock that has more power/current.
You are definitely going to be happy with that setup.
