Happy new year , was hoping to get some help on audio up grades and have several questions. I am looking to add rear speaker and upgrade front speaker aswell as add 2 speaker horns to the rear. thats 8 channels total and 2 4 channel amps. every thing I have purchased is 4 Ohms. I have got a decent deal on everything but its all mixed match brands. I am feeling I should have done more homework now that I see all the plug and play brands out there but committed to what I have now. So to help with install I recently ordered DSR1 Rockford Fostgate/Meastro Idatalink. so here is my first question: Is it True when installing rear speakers and amp if you have a RG/SG special you can tap in to blue speaker wire and will not need a flash from dealer to have them work. Is this a fact for 2017? If it is true will I still need a LOC or DSP ? Planning to add aftermartket Amp and rear speakers and keeping harley HU.