Guys i want to know which on is more powerful and reliable , if their both in a nice built custom box and powered by a Memphis 16-MCD4KW 4000RMS @ 1 ohm amplifier ?

Which one will take away the competitions because i have a 94 Civic hatch and the electrical is done amazingly well and fully dynamated im just wondering which one is the Killer , i could fit a 15" too but i dont know if that will be any good. So if u have any ideas on the amp let me know or if a different amp will be better .

I have no back seat so i do have alot of space and how many Db's can one of these beasts reach . Im thinking of getting a nicely tuned box for one of these but i only want one subwoofer to be in the back , trying to build a SPL car BUT if u guys have any better ideas or different opinions on the amp or sub let me know which is better or something out there is much better. Btw the Alternator is 210 Amp's so its no problem , i got it custom made especially for the car .