these may be the subs i run when i get to the point i can afford them ... what would sound better ....at the most i have 25 cubes

They're the same subs, how are they going to sound different? If anything the tuning of the box is going to change how they sound, not the number of speakers.

look up tuffguy40 on youtube he runs 4 18's xcons. So far he's been the loudest at all the M.E.C.A show here in az this year.

i could get 10 morr cubes if i build the box to fit the floor and back wall but this would be just building a box

so all woofers no matter the size sound the same

so all woofers no matter the size sound the same

Correct.

Frankly, I don't think you should be concerned about the sound quality when you are considering 4 18's or 6 15's.

I would do 6 15's cause you have the advantage of more cone area and MOAR POWEr!

I would do 6 15's cause you have the advantage of more cone area and MOAR POWEr!

at this point, just go for more woofers. more of a wow factor.

What kind of electrical upgrades, deading and front stage do u have in mind?

Ill have to agree with mark on the wow factor... plus it SHOULD be a bit louder.

Wish I had money for this kind of build... maybe if I sell my car??? lol

Have you thought about getting 2 21"s instead? Now that's a nice "wow factor"

wow either combo wud be SICK !

how about 4 21s IA