Is it possible to install a subwoofer in an ultra premium?
 

My wife bought the ultra premium (read base model) and while it gets freaking awesome mileage I would like more subwoofer. The model she got doesnt have the upscaled radio system, just the regular. What would be the best way to add a subwoofer without too much issue? Is by chance the harness already in the back or will I need to rewire?

Unless things have changed, there IS a subwoofer in the car. Just a garbage on. Look up in the trunk under the driver's side parcel shelf.

I will be looking tonight for sure. If that is the case, this will be easy. thanks for the lead. Ill let you know what I find.