[Brian in Tucson]

I think you'll find that your old engine with the intermix isn't worth much. Did the old engine start and run before all this? I don't know for a fact that your 02 harness will fit on an 03, it would fit on an 00 or an 01, but that's not too relevant.

I guess I'm saying, if it was a running but bad engine, take the harness off the old engine, use the DME that came with it, and see if it will fit the 03. Looks to me like you did a tactical error--an 00 to 02 would have been easy peasy.

Will the engine crank if you bridge the terminals on the starter? Do you have a good strong ground connection from the starter to the chassis? Are all the grounds in the trunk firmly attached to the chassis?