loudness?
 

i was looking in this local store and i was looking at a 750 watt Scosche 10" subwoofer. i was wondering will that be loud enough of should i go for 2 12's of pioneer 800 watt subs/???? i have a 97 cavalier too .

go with the pioneer for sure im guessin you were in walmart the scosche is junk

Depends on the box, remember that the box is most important than speakers it self...The diference here is a pair of 12's will need more space than 1 10, the other option is to use just 1 12, in a good box.