I'm looking to purchase a new (to me) vehicle in the 2016-2018 year range. Likely a small SUV (CR-V, Rav4 or the like) and I have noticed the HUs on pretty much all the vehicles in this year range have no PRE-OUT on their HU. When upgrading a system like this that are often integrated into a "Entire Vehicle" media/NAV system, how do you (the experts here) upgrade the system? Looking to add amps mostly since the component speakers and subwoofer are not the problem. I'm guessing adding a "Line Out Converter" is out of the question for achieving high quality audio. Gutting the entire system (Which I did with my 2013 Ford Fusion Hybrid) seems a bit extreme, especially if the stock system has NAV. So, how do you upgrade a stock system that has no PRE-OUT?
Thanks in advance.