I have a 2006 xc90 4.4. Does anyone know if you can add the dash center speaker to the base audio system? I finished replacing the door speakers today. I opened the center speaker location and there wasn't anything in there but there is what looked like the same speaker wire harness clipped into a blank plug holder.

 

I've just ordered a 8" 150w RMS subwoofer as well and will be tying it into the stock stereo system...Ideally it will be hidden in the rear quarter panel or by the battery in the back trunk floor. I'll try and add pictures as I go...I think the hardest part is going to be finding a spot for the remote turn on wire.

 

How has this project been coming along? I am very interested in upgrading my sound system.