Can someone please tell me if the bose sub in the 04 Sedan is self-powered or if it's driven by the bose amp? If the latter, then what's the sub's impedance?

Also, I've read some concerns about the size of the cutouts for the rear speakers, but I'm unclear as to if the posts were specifically regarding the coupe or the sedan. Are the speaker wells in the rear doors ( in the sedan ) abnormally shallow or something?

Last thing... if the sub is not self-powered, can someone recommend a place ( other than ebay ) to find a cheap used five-channel amp? When I say cheap I don't mean a jensen