on subwoofers, whats the difference between a 4ohm sub and a dual 4 ohm sub? which one would be best for me? is either or better than the other?

normally when you have a dual voice coil the power handling is larger then the single voice coil. The only thing that a voice coil changes is the wiring options you have. At least thats all i know it does...

If you have 2 4 ohm subs you can wire them to show a single 2 ohm load or two separate 4 ohm loads. If you have 2 DVC 4 ohm subs you can wire them to show a single 1 ohm load, two separate 2 ohm loads, or two separate 4 ohm loads (only use one VC connector) and possible one 2 ohm load. Someone correct me if I'm wrong. It all depends on what your amp is stable too. The DVC subs give you greater flexiblity if you plan on upgrading to a different amp, but usually cost more.

post your amp and what subs you will be getting and how many. it will b much easier for us to help u wire it.

i had a few subs in mind... below are the links to each... the first is the dual 4ohm sub and the second is the same exact sub at the same exact price but is a 4ohm sub not DUAL... the third is a different Pioneer sub

http://www.cardomain.com/item/PIOTSW256DVC

http://www.cardomain.com/item/PIOTSW256C

http://www.cardomain.com/item/PIOTSW251R

i was also thinking about gettin the JL Audio W1
http://mobile.jlaudio.com/products_subs.php?series_id=15


and my amp is a Directed Audio Xtreme... 800 watts
http://www.electronicscity.com/product_info.php?cPath=175_102&products_id=993&osCsid=fc38194335933b518fa227314482abe5


which sub would be the best for this amp?

I would go for the PIOTSW256DVC if they are the same price as the single VC. That way if you ever wanted to upgrade to a different amp, you can still get the benefits of these subs. I couldn't tell if your amp was 1 ohm stable. I also don't know what the blue pioneers cost but I don't think they'll be as good as the PIOTSW256DVC.