What "spearker harness" are you talking about? Are you talking about the HU wire harness? FYI - I didn't need any speaker wire harness when I changed my fronts.

There is no doubt that Crutchfield has some of, if not the, best customer service around. However, you can get most of the same info. that they send you, for free on the internet (sites like this one and others). Although you don't get immediate customer service and answers, boards like this one (and others) provide some good info and help as well. A deck install and intalling some components is something that many on this board could do in their sleep and are more than willing to help someone out with - if and when questions arise.

EDIT:
Is this the harness you are talking about?
Wire adaptor

You can get that if you just want to plug and play, but if you have a few extra minutes and don't mind just cutting the wire, you can go to your local Radio Shack and get somthing like this female connectors and just attach them to the OEM speaker wire and then attach them directly to the speaker. Whatever you feel comfortable with.