Stereo & Electronics - help with amp choice

Im looking at buying one JL 13w3v3 sub.Problem is I dont know much about amps so What would be the best for this sub?

Should I get the 2 or 4 ohm one?

Would this sub sound better in a sealed or ported box?

For sound quality go with a sealed box, they also help the longevity of your speaker, and require less space than ported or vented enclosures. Hifonics amps always worked for me they have one for every application, they put out the power they say they should and are reasonably priced. But MTX, rockford, Kicker are all excellent amps it just matters on how much you are willing to spend. And i'm not sure on the impedence of that subwoofer... is it a dual 3 ohm?

sealed or ported is all preference. I perfer ported. I dont know if it affects the longevity like stew said but its louder and I think it sounds better. depends on what kinda music you listen to too. ported does take a bigger box though

its a 400 watt rms at either 2 or 4 ohms. its only a single voice coil so just get a mono amp the puts out around 500 rms to a channel at whatever ohm you decide to get. i would get the 4 ohm model that way if you decide to get another sub in the future you can wire it down to 2 ohms. heres a wiring guide for woofers http://www.rockfordfosgate.com/rftech/woofer_wizard.asp?submitted=true&woofer_qty=2&woofer_imp=1