The Kappa's have a high sensitivity rating of 93 db so the X802-5 would be fine. A good high sensitivity 8" sub in a properly sized box would fit your needs. They typically spec a small box.
5 CH specs from Stinger site.
Model Number MT-1000.5
Channels 5/4/3
Continuous Power (RMS)
(<1% THD @ 14.4V) 150W x 4 + 500W x 1 @ 2Ω
75W x 4 + 300W x 1 @ 4Ω
300W x 2 @ 4Ω
700W x 1 @ 1Ω - CH5
S/N Ratio @CEA Standard -90dB
Input Sensitivity 0.5v-11v
Gain 0.5v-11v
Frequency...