What sound system do I have?
 

I'm looking to upgrade the audio system in my 2008 Volvo s60, FWD, and I'm trying to figure out if there's an amplifier in this car. I had the HU-650 unit, but have since upgraded to an aftermarket stereo. I have 6 speakers that I know of, 2 in the front doors, 2 in the rear doors, and 2 in the parcel shelf. There's a speaker grill in the dashboard but I'm not actually sure if there are speakers in there or if it's wired for aftermarket use. I've looked everywhere for the amplifier if there is one, and found a box under the driver seat as well as one behind the carpeting in the trunk close to the driver side tail light. Could anybody help me out?