jl audio 13w7


hi everyone, a guy in my town has a couple new subs jl audio 13w7 for $1000 (subs only no cabinets)

i dont know anything about diy subwoofers.
i was going to use a jbl synthesis s400 to power these ( i think it might be a little weak for these subs.

are these great subs? will they compare to jl fathom series subs?

also, do i just build a six sided cabinet for each sub?
excuss me if my terminology is off, but do i need a dead passive woofer on the box aswell? how about extra wood inside the box to channel the airflow? is the 13w7 a car sub or a home theater sub?

please help me with your opinions.
thanks so kindly
nineballg
thanks bradearles for your response.
one thing that still confuses me is the ohm factor.
i believe that jl audio 13w7d1.5 is their exact model number. my jbl amp has a 4ohm and 8 ohm switch on the back of the unit.

i think the jl 13w7d1.5 has a lower ohm the 4 it might be 3 or 2 (im not sure)

will the ohms be a factor? will it damage my amp or will the subs get damaged from my amp? i obviously dont understand how the ohms work.
thanks alot
i just found out that the jl audio 13w7d1.5 are dual 1.5 ohms. im not exactly sure what that means tho.
If you want to get your moneys worth, buy some good hi powered amps that are stable to the drivers ohm ratings