what car are you gonna install it?

nowadays underseat sub are getting hotter, some are able to hit like a 10 inch box at the trunk...

by getting the sub, i think you better think of what kind of system you are gonna be using first.

If your system are only hu, front spk and the underseat sub, then you need to go for better sub.

if your system are more complex, more ability to tune like you have processor or a headunit with good tuning options, then u can get cheaper sub.

for city, it will be slightly came out from the rear of the seat..since under city front seat not much space..