First, thanks for the quick response! Sadly no, I just have the HU 650 (or whatever the name is) it's the lowest audio stock system that was available for my car. No extra speakers above, unless you mean the little 1.5in by 1.5in things up by the door handle? I'll send a pic tommorow just to clear it up.Well, I doubt you will be happy with the visual aspect of the install. Sure 05-10 aftermarket panels are WAY better than 01-04 units, but they still don't look OE at all.
Do you have premium sound? i.e. can you see midrange speakers above your main 6.5" speakers in the front doors? If so, they may not have the parts on-hand to connect to the under-seat amp.
FWIW, I was way happy to ditch my HU603 for a JVC. Although OE units sound good, they get flaky quickly. But to be truthful, this is an easy job. With the OE Volvo panel, all you need is the receiver, the plug kit, the antenna adaptor and some wire crimpers. You should DIY. As an aside, when they get done, BE SURE TO CHECK FOR THE SRS LIGHT BEFORE YOU DRIVE AWAY. If its on, they need to pay to get it turned off at the dealer.