[bl420]

350w will be more power to the sub but sound quality has nothing to do with power ratings...

you can have a dual voice coil wired in 2 ways.

parallel and series

a dvc 4ohm sub can be wired parallel to have a load of 2ohms on the amp
a dvc 4ohm sub wired series will have a load of 8ohms.

it depends on how you wire it
http://www.edesignaudio.com/wiring.php

for example my previous subs were 2 dvc 4ohm subs
but since i wired both subs in parallel it had a load of 1ohms

of course you need an amp that is 1 ohm stable

so check your amp if its capable of going to 1ohms, if it can you could get around 600w

 

[bl420]

alot of companies do offer 2 ohm and 4 ohm dvc
just keep that in mind.

any of the top end subs manufacturers will do this

 

[bl420]

what kinda subs do you have... did you buy them already?

if not what kind are you looking at?

also did you find out if your amp is 1ohm stable?

 

[bl420]

just make sure you wired the sub in parallel and you should be good.

 

[bl420]

its usually around 24 hours on low volume