Which sub is better... what are their advantages/disadvantages

thanks

Neither. match the woofer to the amp for trhe best performance.

Decide on a sub and amp and then buy the correct coil configuration when ordering the sub. Most have coil configuration choices.

So... would I be right to say that if I wanted to wire two 12 inch 4 ohm subs in parallel to give me 2 ohms... would all I need is a 2 ohm stable amp?

is there any online literature for the beginning enthusiast?
thanks

Yes.

You would want an amp that is 2ohm MONO stable.

If it is a 2ch amp it should be 1ohm stereo/2ohm mono or if it is a single channel amp then a 2ohm stable model.

dude - go to www.jlaudio.com/tutorials and read it all. excellent information