Infinity Basslink Behind the Seat in Double Cab

I am upgrading audio and have an older 10" Boston Acoustic Sub.
Locally someone has an Infinity Basslink powered sub.

The demensions on the Basslink are 12.5 X 14.5 X 8.5 depth.

I saw some people have put it behind the seat on the floor but that is not an option for me as sometimes three kids in the back seat.
I do not need "hear it in the car next door" bass.

1. Has anyone mounted a Infinty Basslink behind the rear seat? I have not removed the plastic but it seems really close.
2. The second option is to build a box for the Boston Acoustic and mount there.


Thoughts?

Thanks in advance.