Good Sounding System

Concerning mids/highs with amps. What difference does it make if I have my speakers hooked up to the head unit or to an amp. Because I had a pair of 12 in ch audiobahns in a big bandpass box (not sure how big exactly) then just stock speakers hooked up to the Head unit and it sounds fine to me. What would be a difference if I hooked them up to an AMP. Also what would be the differnce if I were to buy 2 pairs of new speakers and hooked them up to an amp with the subs?

I think you will get better sound from an aftermarket speaker powered by an amp.

Like I get big ass bass from the back n just turn the low down to -6 and mid and high up to like +4 on the head unit. Is that wrong?!

if you already like the sound, then it's probably fine to leave as is. unless you think there's something missing...

audio is all about the listener, if you don't think you're missing anything then don't bother with anything cause you might not be able to tell the difference, whereas others can

if you upgrade speakers you would only have to get an amp for the speakers if they're more powerful then the head unit can handle or if you just want to have more control over the speakers

The biggest benifits of using an aftermarket amp on mid-high speakers are more power before they distort and frequency seperation if you use a crossover. If its done right it will sound much better.