I agree. The Crossfire wiring is very complex as the lighting system is also connected to some very expensive control modules including the Security system control module and the Body control module. If there is a mistake made while wiring in a DRL relay and you short out one of these modules, it could get very expensive. Also, you will want to rectify the wiring that was performed by the previous owner.
I purchased the canadian switch from a dealer for $432 and replaced it myself. It was a quite tricky getting the dash pieces apart then there were about four wiring harnesses that plugged into the switch.
I think the dealer is your best alternative.