there is a spot next to where the wiring harnes plugs into the radio that is not used. Is this just for the optional disk changer or is there an adapter to us it as a sub out? Are there any factory radios with the sub outs? I just uninstalled my Sony X-Plode (apropriate name) and realized the factory radio sounded much better then the Sony other then my sub.

 

Thats because Sony Xplod car audio stuff is junk. Usually factory radios don't have pre outs. What you can however do is get a line output converter and tap into the rear speaker wires and run it off of those. The only really downside to this is if you fade the speakers all the way to the front or anything like that it will turn your sub off. I ran a setup like this for a while until I put a new H/U in.

Another thing is some amps have speaker level inputs. If yours has these you don't need the line output converter as it does the same thing it's just built into the amp. I used a converter with mine even though my amp had it built it. The only reason I did is it was all wired up when I got the truck they had just unplugged the amp from it so I plugged mine in. I've since rewired the whole stereo pretty much as I'm not running 2 amps, components up front, coaxials in rear, and 2 12" subs with a Alpine H/U. As you can see I've come quite a ways since I had stock everything with a 10" sub on a 320watt rms amp. It did however work fine and actually sounded really good. Pretty much that was the biggest thing the factory setup was lacking. It just didn't have bass to it. The single 10" sub fixxed this.