1ohm or 4ohm amp for my sub? experts needed

[Ianimal 10+ year member]

alright im looking for an amp for my diamond 500w rms 10" 2ohm dual voice coil sub.....

i know the less ohms the less sound quality but if i can (which i can) get an amp that can produce 500w rms stable at 1ohm or a different amp that can produce 500rms at 4ohm which one is better.....keep in mind (and im not sure how this works) that my car is a 12v battery...(please explain what effect this will have depending on the amp, because ive noticed some amps say 12v and some say 14.4v)

some of the amps ive been looking at are...

Alpine MRP-M1000

600x1 rms at 4ohms

Polk audio 400.1 (12v)

400x1 rms at 1ohm

rockford fosgate P500-1bd

500x1 rms at 1ohm

Click to read more...

 

[Ianimal 10+ year member]

so what do you guys think?

1ohm @ 500rms

or

4ohm @ 500rms

 

[iApex 10+ year member]

I'd go for the 1ohm just because it's cheaper to get an amp like that, rather than finding one to run high rms at 4ohm.