I just recently purchased my new 2018 RT Limited. Previously, I had a 2015 RT base model. The difference that I've noticed is that the stereo system on my 2015 sounded better and louder than my new 2018. On my 2018, I'm at maximum volume before I can actually hear my music whereas, my 2015 was loud at 3/4 of the volume with a little more left to increase. My question is whether anyone know of any places in the Memphis or close surrounding areas that can improve the quality of my audio (change speakers and add small amp) without cutting into any of my wiring and voiding my warranty? Plug and play is preferred. If so, please give me the name and contact info.