Looking to add subwoofer to stock head unit

I am looking to add a subwoofer to my stock stereo to take care of some of the low end. I used a similar setup in my 4Runner where I upgraded speakers to focals and added an 8” powered bazooka tube. The tundra is limited on placement options so I was looking at some of the slim subwoofers to install under driver or passenger seat. Has anyone done this to a stock head unit? Eventually I will upgrade the head unit but for now just looking to add a little bit of punch. I am looking at the Kenwood ksc-sw11 - seems we’ll reviewed and price is reasonable. Have also looked at the pioneer version and the infinity bass link.

 

I have a Kenwood ksc-sw11 in my 1st Gen Tundra 2006 Dbl Cab under the back seat. It want rattle the windows but adds some decent bass to my system. It's easy to install for sure. I put the jack in my tool box and put the subwoofer under the seat in the jack compartment. I have had it about 3-4 years with no problems.