I found this plug under the passenger seat. I think it is for the power seat option, just wanted you guys to verify this...

No way, the wires are way to small for that amount of current that the seat motors pull, that's likely for the Infinity amp.

These cars came with an amp stock?

If you bought the sun and sound package they did, yours could be one of them that is pre wired for it in case it was installed.

How come there's that many wires? I've wired many amps and subs and none of them required more than 5 wires. And they were not all in a single connector, they were separate.

I'm pretty sure an amp would require just as much power as a seat, especially if its a quality one.

It'd be nice if somebody else could look under their seat and tell me what it goes to.

That connector is a connector for the optional Infinity amp, It provides power for the amp, as well as leads out to the speakers.

The signal in from the radio was sent over a 5-pin, xlr (round) connector. You can install an infinity amp, but you’ll need to locate, under the carpet, or buy one, to connect to the factory radio.

Ok, so it is for an amp. Thanks guys!

I don't need an Infinity amp, I have a 750w JBL in the trunk

Yup just changed mine out!