I would go with the 500/1, if you have no plans of upgrading. But if you went with the JBL 1200.1, you can always add another sub, and still give adequate power. You can overpower a sub, don't worry about it, the way subs are blown is from abuse. I would go with a sealed enclosure, you can always use a sound deadening material to fix your rattles, and with a ported box, you would be working against your SQ. As far as wiring I would go with 4 gauge wiring, you can possibly get away with 8 gauge depending on how long you need it. If it's more than 8 feet, I'd say 4 gauge. If your gonna go with the JBL, then 4 gauge for sure.