Good 12v constant?

[Cartel]

I bought a little powered sub. Just to add a little better quality to my completly stock stereo. I need a good constant 12v source. My best bet so I dont have to wire too much up is the powered seat? If thats a good one anyone know what wire? Thatd be great if not i suupose i can get off my butt and start poking some wires with the test light. If not anyone know a good source. IM just trying to avoid wires and stuff trying to keep the interior as stock as possible. Thanks guys!

[Sandman]

You'll need to run the power for it from the battery. Don't forget to put a fuse as close to the battery as you can.