ok im getting a 2007 grand prix GT with the monsoon sound system next week from a friend.

my questions are

1. is it possible to hook up subs to the stock head unit?

2. could i use the monsoon amp to hook up the subs?

3. can i replace the monsoon amp and hook subs up to that one?

4. if i hook the sub to the amp, do i need to run any wires to the head unit?

thank you.