I know its a f150 site but doing internet searches for this stuff I usually end up here, so....

I blew my stock sub the other day (speaker foam seperated from the actual speaker) and I wanted to keep the stock enclosure and just add a new speaker. I used to be into huge systems but I just wanted to leave this stock. Well the only sub that my local shop had in stock that would fit was a 4 ohm Memphis 8, they said "this is what we put in the stock boxes". Well I put it in and it sounds terrible, way worse than factory, no punch at all. I'm looking for some help now for stock system specs.

Whats the ohms of the stock sub?
Whats the output (watts) of the stock amp?
Which wire is positive and negative on the amps output?
(black w/white dashes has small spade terminal, Solid black has large spade terminal) I've swtched them and it sounds best with the black w/white hooked up positive

Does anyone know if theres an aftermarket amp that will fit in the stock location?

Any help would be greatly appreciated. Thanks