Amp question about power 2 or more woofers:
 

Hi im about to sell my sound system and i wanna buy a much bigger one if i buy 2 or 3 12 inch subwoofers rated at 1000 rms power should i buy a 2500.1 or 3000.1 mono amp OR buy a amp thats 1000 rms and power a 1000 rms subwoofers.

You need a game plan first. Decide on whether or not you are going to be using 2 or 3 subs as this will dictate the type of sub and the amp(s) to be used. Decide on what size sub you are after, decide if you want a one note wonder system or something that you can listen to on a everyday basis.

12 inch woofers for sure and every day basis

More info is needed. What vehicle is this going in, what cd player is used, are you after new or used equipment? Are you shopping by price or performance? Are you going to build a proper box for the subs?

2000 hyundai accent, alpine 2006 model mp3 deck, new equip, shopping for performance.