I hear ya. I miss the old days when upgrading a stereo was simple. Being forced to pay an extra $200+ on a head unit sucks too. I recently replaced my door speakers with Pioneer TS-66844Rs from Crutchfield. Cleared up mids and highs but its lacking bass. Makes me want more. Looking at headunits and posssibly a powered sub as well.
Here is the other Metra at Sonic that isn't touchscreen: Metra 99-5823CH | 2010-up Ford Mustang Single/Double DIN Dash Kit