I use my touchpad in my Tacoma all the time.. Does it sound better than my Pioneer AVH P4200DVD deck that's installed, not even close. I can take the same mp3 file, play it on my touchpad to my deck using the 3.5mm cable, for good clean volume my deck will need to be at vol 34 and the touchpad at full or one click down from full.
This is the same if I use my phone for my media source.
Same exact file playing on my Pioneer deck vol 27, no distortion or clipping at all, vol 34 would blow out my speakers if I tired that playing the song off the deck vs. the touchpad.
I don't have a stock stereo, I run all Image Dynamics top of their line for speakers/subs and use alpine amps.
Anyone running a stock stereo will not notice much of a difference.. Run a high end stereo, you can hear it night and day.