what kind of amp should I use?

I bought a Pioneer TS-W307D4 and i was wondering if how many watt amp should i get and wether I should get a 2 or 4 channel amp?

you want an amp that pushes ~400 rms at 2 ohms. i would sugguest a small monoblock like this one:
http://www.crutchfield.com/S-FRaJqRtSO6n/cgi-bin/ProdView.asp?search=Profile+VENDORID489&searchdisplay=Profile&i=489AP1000M