car audio noob question

[reem]

Okay i have recently just got a saxo and this is my first post on these forums and i am asking for some advice/help on my audio system that im going to set up i have already bought a perfectly good headunit but the ordinary saxo speakers are just not doing it for me so i was thinking of getting these for the back speakers http://caraudiosecurity.com/shop/pro..._id/13594.html and for the front http://caraudiosecurity.com/shop/pro..._id/13597.html and i was wondering if i would need an amp to power these?

the headunit i have is http://bit.ly/hibgIL

i also plan on getting a subwoofer (1000w)