I have used volvoparts.com, they discount about 15-20% depending. I, too, asked my dealer if they discounted or matched prices and I think the person took a stroke because it took a few minutes to answer me (no); I think they were stunned that someone had the guts to even ask such a thing!!! I have also used an outfit in California called Volvo & Saab Dismantelers or something very close to that. I have bought a lot of oddball pieces from them that probably would have cost an arm and a leg from the dealer (an example would be the carpeting--not mats, the stuff under them--my local dealer wanted $800..gasp!!..I got it from them for $100 + 25 shipping and I live on the east coast so I thought that was very reasonable).
Anyway, I hope this is of some help.