best subwoofers

I have an interesting question. I have an Alpine MRD-M500. I currently have two 4ohm Pioneer 12's, so basically im using the amp at half of the power. I wanted to know what would be the best 2 ohm subs so i can get the maximum output from the amp?

GAHHHH!!!!! I am about to pull my hair out with people thinking they HAVE to run an amplifier "loaded all the way". There will be less than 3dB output difference between a 2 ohm load and a 1 ohm load (especially with that amplifier, as it's output DOES NOT DOUBLE between 2 ohms and 1 ohm). Since 3dB is commonly recognized as the smallest difference the human ear can actually hear, you will NEVER NOTICE THE DIFFERENCE BETWEEN A 2 OHM LOAD AND 1 OHM LOAD!

An inaudible output difference with higher distortion, lower efficiency and less control over the woofers is not worth it. Are you happy with the system as it is? Then leave it alone!

I'm sorry to have to put it like that, but I'm serious... I am about to go bald explaining this to people!

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

"I currently have two 4ohm Pioneer 12's".

If they are single VC, 4 ohms + 4 ohms = 2 ohms. That amp is stable to 2 ohms. So how are you only using "half the power"?

Well thats what i was told when i got it hooked up because I dont know how to set a digital amp correctly. I like how it sounds but i know it could sound a whole lot better and i wanted to get the best sound for my money!

A Class D ("digital") amp is set and loaded exactly the same as any other amplifier.

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

I dont know how to set it because i never used a digital amp before. Well do you think you could help me?