Maybe you're done by now but as for the connectors, the wire nuts you mentioned require cutting the wires so you have ends to twist together. Technically fine I'm sure but it makes one squeamish to be cutting wires in a new vehicle. Any auto parts store or Radio Shack will have 'in-line' splice-type connectors, which have two little half-pipe looking channels the new and current wires fit in, then you close and squeeze and the connector itself has metal prongs that punch into the wires to make the connection. Neat and effective.