was just wondering cuz im gonna upgrade to the alpine 9813 soon and i have the factory sub right now. will i still be able to use it or should i just sell it? thanks

 

I believe as long as you aren't running an amp to your speakers, you should be ok. I replaced my deck with a pioneer and didn't have a problem until I installed an amp. Just plug the wiring harness for your new deck into the sub adapter.

 

Yes, I have the stock sub with an Alpine 7894. Any deck with an internal amp will allow the sub to work as it bridges off the rear speaker outputs.

 

will using the stock sub degrade the speaker sound quality then, since it bridges off the rear outputs? am i better off with upgraded speakers w/ the deck or upgraded speakers w/ deck + factory sub?

 

The presence of the sub does not affect the sound quality of the speakers.