When I put my new stereo in the dash I was forced to include a new wiring harness to replace the factory. So the answer to any other wires is no, to my knowledge. For question #2, no I have not yet put in new speakers, but i am looking to possibly find some new ones this weekend. If you want to replace the dash the size is a 4"x 6" speaker, or you can order a custom bracket for a 5 1/4" speaker in one of the catalogs. Hope I was able to help ya, and wish to hear if you add any new speakers.