I'm looking for a subwoofer for an Onkyo txsr607 amplifier.

I'm not sure which of these would be more suitable for a 20-25 square meter room.

A 100 watt Klipsch KSW-10 or a 420 watt Klipsch Sub-10. Im not sure what is a difference between these units except wattage and a slightly different band range just by 1 hertz in the case of the more powerful unit. Both subwoofers are in the same price level.