Whats better having the system under the seat or put one in the middle like from the middle floor to the top of the seat.

 

Under

 

Depends on certain things. Like do you want stealth install, do you need the floor space in the middle. You have more sub options putting something in the middle of the floor and can get almost any 12" sub there. But, you loose the floor space and it is right out in the open for all to see.