My next goal will be to produce a track using all low-quality mp3 files and samples, just to show that low-quality can still sound "good".
And yes, I agree... mixing w/ mp3 is a bad idea. But yet and still... we still have bit-crushing capabilities for a reason. Low quality audio sometimes as a certain "grit" or tonality that we may actually want in a few cases. If I wanted to make a early 90s hip-hop sounding track... I might try mixing w/ mp3s.
Can't wait till I can mix good enough to pull this off! lol