what ohm load does the amp do what power at? I am guessing you amp is 600x1 at 2 ohms. If this is the case I would do a single RE SE 12. It will pretty close to 300 for the sub but well worth it. Much better SQ than any of the other subs listed, and louder than any single sub mentioned. Again, they are more expensive, but nyou get what you pay for.