Substantially cheaper than the stock Volvo stuff. I ended up consulting with the Canadian VDO importer/distributor, Forster Instruments in the Toronto, Ontario area. They gave me excellent and very detailed technical advice on which components to buy. You might find a US dealer for VDO, and ask their advice, or call Forster Instruments.

I think this the right company (click link): http://www.goldbook.ca/mississauga/Truck-Equipment-Parts/freelisting/1619846.html