You need one of the higher monster amps, not only because of power or the fact tubes won't drive those 15's to well but fact is any high efficiency speaker in order to drive rock bottom bass in my opinion and experiance Needs as Much Current as possible, this has nothing to do with the size or Wattage an amp can produce really in comparison, because you can buy a Coda amplifier running 100 watts and still have 100 amps of current per channel, most large amps have this without needing to go to such high priced pieces and that is why most of the suggestions have been of high wattage amps, not really because you need 300 watts to drive 99 db speakers, but you need it to control those woofers and that comes in the form of HIgh current capabilities per channel, and many times equates to needing dedicated power supplys and many switching devices(Transistors) to do it, so you could go mono blocks and achieve all this as well. I suggest for the money, 2700.00 will get you about the highest current possible with high efficiency mono blocks on top of it and they don't even create heat in the room, ant those would be Odyssey Extreme mono blocks. Take a look at audio review.com and you will find how stellar these monos rock if you are truly interested in bullet proof and 20 year warranty amps. Oh and they sound incredible, but I do not own them, many here do however.