The KCW1 is one of the most affordably priced, effective subs out there that is actuallyt MADE for road use. The home stereo units have the tone, but their road-worthyness has yet to be proven.
Use the line out from your kb amp ( which, BTW is more than TWICE the cost of this sub )and go into the sub. Another way is to simply add a bass amp that has a crossover. Filter out all the frequencies above 180 Hz or so ( personal taste ) and it'll give you that "kick" you want!