i have found a full plug-in-play harness for the sw20, or spyders. they have factory harness extension, plus a E-manage harness already wired in.
http://www.boomslang.us/emanage.htm
or search factory harness extension at yahoo, and click the link that has boomslang as a web site.
really neat. and a lot easier, and u dont have to touch ur factory harness.