2 x 8w7 or 2 x10w7

i need help deciding on a setup.... i m going to install 2 subs into the seat well of my backseat( i took out my back seat) 2001 mustang convertble. i ordered 2 8w7s but i m not sure there is going to be bass..i like deep tight bass...but its going to be installed right behind my head.... wat is going to be the difference between the 8's and 10's...

If you like deep bass go with the 10's the eight's will not cover the low end spectrum that you might be looking for.

10's will sound better. Only if you get multiple 8's would you get some power.I need quality equipment, feel free to donate.