Kenwood KAC-646x with subwoofer?

I have a 2011 Honda Pilot. My pilot has a subwoofer in the back stock. I want to replace with with an after market subwoofer possibly Kicker 40CWD104 it is a free air sub. I know it will power the sub fine rms for sub is 50-300. Amp runs @ 124x2. I'm wondering if this amp and that sub would be compatible (specs for amp at bottom and sub too). If 4ohm sub won't work wit it what ohm would ect so on and so forth. Just need some electrical advice and wiring/ compatability I suppose. I know this amp is old but its sitting around the house doing nothing. I don't want anything louder cuz it is a family vehicle just want a bit more bump than the 35w the sterio is pushin out.

sub specs
Highlights:
-10" subwoofer with dual 4-ohm voice coils
-injection-molded polypropylene cone
-ribbed foam surround
-suitable for free-air use
-power handling: 50-300 watts RMS (150 watts per coil)
-peak power handling: 600 watts
-frequency response: 30-500 Hz
-sensitivity: 86.2 dB
-top-mount depth: 4-3/4"

Amp
KAC-646X 4-Channel Power Amplifier
Bridgeable 2, 3 or 4 channel output
Max. Power output 50W X 4 (4Q) - 25W x 4 at 4Q 14.4V (0.08% THD) RMS power output
35W X 4 at 2Q 14.4V (0.8% THD) RMS power output
Tri-mode operation
A + B/A input selector
A/B independent level controls
High-pass filter (150Hz) and low-pass filter (80Hz)
DC-DC converter power supply
MOS FET current drive
Gold plated line in/out, speaker and power supply terminals

Specs say it's 70x2 bridged at 4 ohms. I'm curious where you came up with 124x2.

Typically a 4 ch amp is a poor match for a single subwoofer, but since the cwd104 is actually a dual voice coil sub you COULD bridge the amp and run one bridged channel per sub. You'd need to pay close attention to getting the settings on each pair of channels.
A much better option would be a mono amp that's around 300w rms at 2 ohms.