No, you need an amp. just hooking up subs to a stock deck wont do any good. Even hooking them up to an aftermarket head unit wont do any good. Subs need an amp to give them enough power
The only subs I'd hook up to a stock deck would be some Sony xplodes seeing they can only handle about the RMS put out by a stock deck :P ... but its not good for the h/u due toe the difference in impedence unless you have 4ohm subs. Just save your money and get an amp..
Stock deck wont even power a55plodes. Since most decks are rated in WLS ratings (When Lightening Strikes) (26v or some ungodly ohm load)....you wont get crap out of them.
Even the best decks out there will do no more than a few w over 10 on a good day regardless of what the deck, or the manufacturer, say. If that.
Consider this....imagine your avergae 50x4 amp. Now imagine that in a deck, with the transport, and all the other technology in there as well....and it does 50x4 STILL?
i don't think you can do a "WLS" rating on a deck...only speakers and subs. thats when you keep burping sh-t loads of power to a speaker or sub until they blow.
the older Alpine V-Drive decks do a true 26 watts RMS X 2 if wired correctly.